  July 12, 1993         [NOT FOR PUBLICATION]

                    UNITED STATES COURT OF APPEALS
                        FOR THE FIRST CIRCUIT
                                             
No. 92-2367

                      UNITED STATES OF AMERICA,

                              Appellee,

                                  v.

                          JOSE ALGARIN-ROSA,

                        Defendant, Appellant.

                                             
No. 93-1006

                      UNITED STATES OF AMERICA,

                              Appellee,

                                  v.

                     EDUARDO GONZALEZ-RODRIGUEZ,

                        Defendant, Appellant.

                                             

            APPEALS FROM THE UNITED STATES DISTRICT COURT

                   FOR THE DISTRICT OF PUERTO RICO

            [Hon. Raymond L. Acosta, U.S. District Judge]
                                                        

                                             

                                Before

                      Torruella, Oakes* and Cyr,

                           Circuit Judges.
                                         

                                             

                   
*Of the Second Circuit, sitting by designation.

     Jos  C. Romo Matienzo for appellant Gonzalez-Rodriguez.
                          
     Carlos Vazquez-Alvarez for appellant Algarin-Rosa.
                           
     Esther Castro  Schmidt, Assistant  United  States Attorney,  with
                           
whom Daniel F. Lopez Romo, United States Attorney, and Jos  A. Quiles-
                                                                      

Espinosa, Senior Litigation Counsel, were on brief for appellee.
        

                                             

                                             

          Cyr, Circuit Judge.  Appellants challenge their convictions,
          Cyr, Circuit Judge.  
                            

under 21 U.S.C.   841(a)(1), for  aiding and abetting the distribution

of 997.3 grams of cocaine.  We affirm.

                                  I

                              BACKGROUND
                                        

          We  review the evidence in  the light most  favorable to the

prosecution with a  view to whether a  rational jury could have  found

the defendants guilty  beyond a  reasonable doubt.   United States  v.
                                                                  

Cruz, 981 F.2d 613, 615 (1st Cir. 1992); United States  v. Tejeda, 974
                                                                 

F.2d 210, 212 (1st Cir.  1992); United States v. Ortiz, 966  F.2d 707,
                                                      

711 (1st  Cir. 1992), cert.  denied, 113 S.  Ct. 1005 (1993).   Around
                                   

April 6, 1992, a  confidential informant received  a tip that  cocaine

could  be  purchased at  "Los Companeros,"  an  auto body  repair shop

operated by  two brothers, Eduardo Gonzalez  Rodriguez ("Eduardo") and

Luis Gonzalez ("Luis").   The informant went to the  shop, accompanied

by one Harry  Burgos, and  there encountered Jose  Algarin Rosa  ("Al-

garin"), apparently  an employee.   The informant asked  Algarin about

the possibility of  purchasing a  half kilogram of  cocaine.   Algarin

told the informant  that in order to purchase  this amount, the infor-

mant would need to talk to Luis.

          As the informant was leaving the  shop, Luis arrived, accom-

panied  by Eduardo.   Algarin  made introductions.   With  Algarin and

                                  3

Eduardo present, the informant again asked to purchase a half kilogram

of  cocaine.   Luis consulted with  Eduardo and  offered to  sell one-

eighth of a  kilogram of cocaine for $3000; the informant declined the

offer.   Luis then indicated that a  large shipment was due from Vieq-

ues, Puerto Rico, and that when the shipment arrived he could sell the

informant  a full  kilogram  for $16,000.   The  informant tentatively

assented.

          On  April 13, 1992, the  informant met again  with Luis, who

stated that he had received the shipment from Vieques and was ready to

complete the kilogram deal.  The informant gave Luis his beeper number

and left, ostensibly to get the purchase money.  Around 3:00 p.m., the

informant returned to the repair shop, accompanied by Ruben Diaz Padro

("Diaz"),  a federal  undercover agent.   Luis  and Algarin  were both

present.    Before  the  transaction could  be  consummated,  however,

Eduardo entered and warned  Luis that there were police nearby.   Luis

thereupon arranged to  meet the informant on a  nearby road.  Accompa-

nied by  Diaz, the informant drove to the site of the proposed rendez-

vous,  and parked as  instructed.  A few  minutes later, the informant

and Diaz observed Eduardo  drive by in a wine-colored  BMW automobile.

After several passes,  Eduardo pulled over and parked in  front of the

informant's automobile.  Luis  pulled in behind.  Using  hand signals,

Luis  attempted to  lead the informant  to a third  site, with Eduardo

following in his  own car.   Because the  informant was  uncomfortable

with this change in plans, he declined to follow, and drove away.

                                  4

          Later that  afternoon, Luis  called  the informant's  beeper

number and agreed to complete their kilogram transaction at the repair

shop.  Eduardo greeted the informant on arrival and instructed him not

to park in  front of the shop.   As the informant and  Diaz made their

way  into the office, Algarin reassured the informant of Luis's hones-

ty:  "Do not be afraid,  they do not deal with tricks."   Eduardo, who

was leaving the office as the informant met with Luis, advised Luis on

how to remove the  cocaine from its bag:  "That is not the way that it

is done.  Don't take it  out like that."   Shortly thereafter,  at the

informant's signal, federal agents  raided the repair shop.   Luis was

arrested in  the office.    Algarin attempted  to  run away,  but  was

arrested after  a scuffle with DEA  agents at the shop  gate.  Eduardo

was  arrested on the street nearby.   All were indicted for aiding and

abetting the distribution of cocaine.

          The defendants were joined  for trial, over Eduardo's objec-

tion.  On May 4, 1992, the defense filed an omnibus discovery  motion,

seeking, inter alia, "all  information which may be used  for impeach-
                   

ment  of government  witnesses."   The  government  disclosed that  an

administrative fine had  been imposed on  the informant for  marijuana

possession  in New York.   The government disclaimed  knowledge of any

other impeachment material relating to the informant.

          Ultimately, Luis entered a  guilty plea; Eduardo and Algarin

went to trial.   In an effort to discredit  the informant's testimony,

the defense  called Esteban Garcia  Rosario ("Garcia"),  a former  ac-

quaintance of the informant, who testified that the informant had used

                                  5

and dealt drugs in the past.  To rebut Garcia's  testimony, the prose-

cution  recalled the informant.  The informant admitted knowing Garcia

and, later, on cross-examination, admitted  that he had once purchased

drugs from Garcia "for  a friend."  Both defendants asserted  that the

government  should have  disclosed  this information  prior to  trial,

relying  on Brady  v. Maryland,  373   U.S. 83  (1963), and  moved for
                              

judgments of  acquittal under Fed. R.  Crim. P. 29.   The court denied

their motion.

          In the course of his redirect examination by the government,

the  informant was  asked whether  he "had  any personal  knowledge if

[Garcia] was  acquainted with  Eduardo Gonzalez or  Luis Gonzalez  and

Algarin."  The informant responded in Spanish:  "as to Algarin I don't

know,  but I do know that he  [Garcia] bought one eighth [kilogram] of

cocaine from  . . . Eduardo  Gonzalez."    Before the answer  could be

translated into English, both  defendants moved for mistrial, invoking

the rule on "other acts" evidence.  See Fed. R. Evid. 404(b).  Reserv-
                                       

ing its ruling  on the  mistrial motion, the  district court gave  the

government an opportunity to  show that the informant's statement  was

based  on  personal knowledge  of  Garcia's prior  drug  sources under

Evidence  Rule 602.  Eventually, the informant was permitted to testi-

fy:  "I used to visit him [Garcia] at his house and I know that he was

buying from Luis and Eduardo."  A few hours later, as part of its jury

charge, the court delivered a  curative instruction proposed by defen-

dants:

                                  6

          "I instruct you, ladies and gentlemen of the jury,
          that the defendants are on trial solely and exclu-
          sively on  the charge set forth  in the indictment
          and  nothing else.   So  therefore I  instruct you
          that  you should  disregard, that  is, get  out of
          your mind completely, [the  informant's] testimony
          concerning  [Garcia's]  prior  dealings  with  the
          defendant.   It has nothing  to do with  this case
          and it  is irrelevant and you  should not consider
          it at all for  any purpose whatsoever in  your de-
          liberation . . . ."

Algarin and Eduardo were both convicted.

                                  II

                              DISCUSSION
                                        

          Appellants'  first contention  is  that  the district  court

erred  in denying their motion  for mistrial based  on the informant's

testimony that Garcia had purchased "one eighth [kilogram] of  cocaine

from . . .  Eduardo Gonzalez."   Assuming, for present  purposes, that

the informant's  statement was  inadmissible  against appellants,1  we

review for "abuse of discretion" the district court's election to give

a cautionary instruction, rather than declare a  mistrial, to counter-

act any prejudicial effect which may have resulted from the challenged

testimony.  See, e.g., United States v. Bello-Perez, 977 F.2d 664, 672
                                                   

(1st Cir.  1992); United States v.  Sclamo, 578 F.2d 888,  890-91 (1st
                                          

Cir. 1978).

                    

     1Rule 404(b)  provides that "[e]vidence of  other crimes, wrongs,
or acts is not admissible  to prove the character of a person in order
to show action in conformity therewith. It may, however, be admissible
for  other purposes,  such  as proof  of motive,  opportunity, intent,
preparation,  plan,  knowledge, identity,  or  absence  of mistake  or
accident."  Fed. R. Evid. 404(b).

                                  7

          There  was  no  abuse of  discretion.    Even assuming,  for

purposes of discussion, that some improper prejudice may have resulted

from  the informant's  testimony, the  degree of  any such  prejudice,
                                             

assessed  from the  vantage point  of a  "cold appellate  record," see
                                                                      

Freeman v. Package Mach. Co., 865 F.2d 1331, 1340 (1st Cir. 1988), was
                            

plainly insufficient  to  warrant second-guessing  the  trial  court's

judgment  that its jury instruction was adequate cure for any possible

unfair  prejudice.  Moreover,  although appellants now  fault the dis-

trict court's  failure to give a contemporaneous instruction, there is

no indication  in the appellate  record that one  was requested.   See
                                                                      

United States v. Valencia-Lucena, 925 F.2d 506, 513-14 (1st Cir. 1991)
                                

(review "limited to plain error"  where defendant eschewed request for

limiting instruction  upon trial  court's denial of  mistrial motion).

Rather, the court permitted  the defense to draft a  curative instruc-

tion  which  was included  in the  jury charge  delivered a  few hours

later.  "We normally presume that a jury will follow an instruction to

disregard inadmissible evidence inadvertently  presented to it, unless

there is an 'overwhelming probability' that the jury will be unable to

follow  the court's instructions."  Greer v. Miller, 483 U.S. 756, 766
                                                   

n.8  (1987) (quoting Richardson v.  Marsh, 481 U.S.  200, 208 (1987)).
                                         

Whether  or not the brief  interval between the  subject testimony and

the curative instruction was the  product of a tactical choice  on the

part of the defense, it did not amount to "plain error."

          Appellants contend that the government's failure to disclose

the informant's prior dealings with Garcia, in response to a discovery

                                  8

request from  the defense for "all  information which may be  used for

impeachment of government witnesses,"  constituted a Brady  violation.
                                                          

Once  again  we assume,  for  purposes  of discussion,  that  Garcia's

testimony  relating  to the  informant's  prior  cocaine dealings  was

potentially  exculpatory,  and we  accept the  government's concession

that it was material, in the sense that its disclosure would "create a

reasonable  probability . . . that the  result of the proceeding would

be different."  United States v. Bagley, 473 U.S. 667, 682 (opinion of
                                       

Blackmun, J.) (1985); United States v.  Osorio, 929 F.2d 753, 758 (1st
                                              

Cir. 1990).  In order to warrant reversal, however,  a delayed disclo-

sure  of material  evidence  must be  shown  to have  "prevented  [the

defense] from  using the  disclosed material effectively  in preparing

and  presenting the defendant's case."  United States v. Ingraldi, 793
                                                                 

F.2d 408,  411-12 (1st  Cir. 1986); United  States v. Devin,  918 F.2d
                                                           

280, 289-90 (1st  Cir. 1990); United States  v. Osorio, 929 F.2d  753,
                                                      

757 (1st Cir. 1991).  In the present case, the defense was well  aware

of  the informant's prior cocaine dealings with Garcia prior to trial.

Indeed, Garcia  was called as a  witness by the defense,  for the very
                                                       

purpose  of testifying to these  matters.2  Accordingly,  there was no

showing  that prejudice  resulted from  the  delayed disclosure.   See
                                                                      

Valencia-Lucena,  925 F.2d  at 514  ("[T]he fact  that the  government
               

                    

     2During  cross-examination,  Garcia   stated:    "sometime  back,
Eduardo  went to my  house . . . . and  he told me  about his problem.
And, well  since I knew [the  informant] from sometime ago  and I knew
about his past,  I decided that if it was necessary  for me to come to
testify here in court,  to give my testimony in front  of the Court, I
would do so and here I am."

                                  9

failed  to disclose to the  defense before trial  that [its informant]

was a drug user in no way robbed the defendant of a fair trial because

the  issue was fully revealed at trial and extensively explored during

cross-examination").

          Finally, appellants challenge  the sufficiency  of the  evi-

dence, claiming that they were "merely present" at the scene of Luis's

drug  dealing  activities, and  reminding  us that  evidence  of "mere

presence"  is insufficient to  support their convictions.   See Ortiz,
                                                                     

966 F.2d at 707 (1st Cir. 1992); United States v. Francomano, 554 F.2d
                                                            

483,  486 (1st Cir. 1977).   We evaluate their claim under well-estab-

lished standards.  Although "neither mere association with the princi-

pal nor mere presence at the scene of the crime . . . is sufficient to

establish aiding and abetting . . . .," United States v. Alvarez,  987
                                                                

F.2d 77, 83  (1st Cir. 1993); United States v. Aponte-Suarez, 905 F.2d
                                                            

483,  491  (1st Cir.),  cert. denied,  498 U.S.  990 (1990)  and cert.
                                                                      

denied, 498 U.S. 1092 (1991), a defendant's presence at the scene of a
      

criminal transaction is sufficient to support a conviction for "aiding

and abetting" if it is accompanied by additional indicia of participa-
                                                

tion in  or association with  the criminal venture.   See id.  (citing
                                                             

United States v. Rodriguez Cortes, 949 F.2d 532, 539 (1st Cir. 1991));
                                 

see also United States v. Echeverri, 982 F.2d 675, 678 (1st Cir. 1993)
                                   

("culpability  of  a  defendant's  presence hinges  upon  whether  the

circumstances  fairly  imply  participatory involvement").    Here, in

addition  to his presence at  the repair shop,  the government offered

evidence  that Eduardo (1) consulted with  Luis on April 6,  as to the

                                  10

price  and quantity  of  the cocaine  offered  to the  informant;  (2)

watched for, and warned Luis about, police presence in the area of the

repair shop on April 13; (3) accompanied Luis in a separate car to the

site  of the aborted first  transaction; (4) told the  agents where to

park  their car when they  arrived to consummate  the transaction; and

(5) evinced familiarity with (and  some measure of responsibility for)

the cocaine transaction, just prior  to the DEA raid, by telling  Luis

how to handle the  cocaine.  In addition to  Algarin's "mere presence"

at the repair shop, the government presented evidence that Algarin (1)

introduced the informant  to Luis, after  learning that the  informant

sought to purchase a large quantity of cocaine; (2) stood next to Luis

during negotiations with the  informant on April 6; (3) evinced famil-

iarity with Luis's business practices, and sought to offer reassurance

to the informant and undercover agent ("don't be afraid, they don't do

tricks  here"), when  the  informant arrived  to  consummate the  drug

deal; and, finally, (4) ran from the shop, scuffling with  a DEA agent

at the gate, when the raid began.  Cf. United States v. Hernandez, No.
                                                                 

91-2034/5/6, slip op. at 18 (1st Cir. May 12, 1993) (upholding convic-

tion where defendant apparently knew that  an illegal drug transaction

was  about to occur,  lingered inexplicably at  apparent vantage point

outside  apartment, and  attempted to  flee during  DEA raid);  United
                                                                      

States  v.  Martinez, 479  F.2d 824,  829  (1st Cir.  1973) ("presence
                    

itself  implies  participation [where]  . . .  a  companion stands  by

during  a [crime],  ready to  sound  a warning  or give  other aid  if

required.").   Finally,  as  to both  defendants,  we  recognize  that

                                  11

"criminals  rarely welcome  innocent persons  as witnesses  to serious

crimes," Hernandez,  slip op. at 17 (quoting  Ortiz, 966 F.2d at 712),
                                                   

and that Luis's apparent willingness  to consummate the transaction in

Eduardo's and  Algarin's presence  provides some corroboration  of the

jury's  ultimate conclusion as to their culpability.  United States v.
                                                                   

Batista-Polanco, 927 F.2d  14, 18  (1st Cir. 1991).   Arguably,  then,
               

even  if the evidence of  appellants' participatory presence was some-

what thin, particularly in Algarin's case, it  was nonetheless legally

sufficient to support their convictions.

          Affirmed.
                  

                                  12
