267 F.3d 1 (1st Cir. 2001)
UNITED STATES OF AMERICA, Appellee,v.PEDRO GoMEZ-GENAO, Defendant, Appellant.
No. 01-1181
United States Court of Appeals For the First Circuit
Submitted Sept. 4, 2001Decided September 14, 2001

APPEAL FROM THE UNITED STATES DISTRICT COURT FOR THE DISTRICT OF PUERTO RICO
[Hon. Salvador E. Casellas, U.S. District Judge]
Ernesto Reyes Blassino, for appellant.
Guillermo Gil, United States Attorney, with whom Jorge E. Vega-Pacheco, and Nelson Perez-Sosa, Assistant United States Attorneys,  were on brief, for appellee.
Before Lynch and Lipez, Circuit Judges, and Doumar, Senior District Judge.*
LYNCH, Circuit Judge.


1
Pedro Gomez-Genao, an illegal  alien, was convicted of possessing with intent to distribute some  thirteen bales of cocaine, smuggled from a beach in Puerto Rico, and  aiding and abetting two others to do the same.  21 U.S.C. § 841(a)(1)  (1994); 18 U.S.C. § 2 (1994).  He was also convicted of being in the  United States illegally.  8 U.S.C. §§ 1326(a)(2) and (b)(2) (1994  & Supp. II 1996).  He left a fake resident alien card with his  photograph on it at the scene of the crime.  He was sentenced to  twenty years.


2
Gomez-Genao appeals, arguing that his Sixth Amendment  rights were violated by the government's failure to identify a  confidential source, Graciano Santana, who was neither a witness to  nor a participant in the crimes charged.  Santana's role was  different.  He knew Gomez-Genao as "Soler" and Soler had indirectly  and directly bragged to him about the drug smuggling, saying that he  would receive $1,000 per kilo of cocaine for his role.  Santana told  the police, who eventually identified Soler and located him.  The  government's reasons for not turning over the name were fears for  Santana's safety.  The street value of the 325 bricks of smuggled  cocaine was in the millions of dollars, a fact which suggests a large  criminal organization, which in turn underlies the government's fear.


3
The government responded negatively to Gomez-Genao's oral  request, first raised in November 1999, for the identity of the  confidential source.  It withheld the name from the Jencks material  it provided on June 9, 2000.  Jencks v. United States, 353 U.S. 657  (1957).  Nonetheless, Gomez-Genao did not ever move that the  government be compelled to produce the name until June 12, 2000, two  days before the trial began.  Gomez-Genao was given the name of the  confidential source on June 14, just before trial.  He was given  Santana's criminal history as well, and used that history to cross-examine Santana.  The name was given to Gomez-Genao before the court  had the opportunity to rule on the motion.


4
In order to protect the public interest in effective law  enforcement, the government may withhold the identity of a  confidential source.  Roviaro v. United States, 353 U.S. 53, 59  (1957).  There are limits to withholding that information where the  disclosure of the identity of the informant "is relevant and helpful  to the defense . . . or is essential to a fair determination of a  cause . . . ." Id. at 60-61.


5
Gomez-Genao bears the burden of persuasion that he was  entitled to the information, a burden described as heavy.  United  States v. Robinson, 144 F.3d 104, 106 (1st Cir. 1998).  Had Gomez-Genao filed his motion earlier and given the district court time to  rule on it before trial, and had the court so ruled, we would have  reviewed that ruling for abuse of discretion.  United States v. Lewis, 40 F.3d 1325, 1335 (1st Cir. 1994).  However, Gomez-Genao  neither gave the court enough time to rule on the matter pre-trial,  nor asked for a continuance, so he is ill-situated to complain.


6
On appeal, Gomez-Genao has shown neither a need for the  information nor that he was prejudiced by not having the information  before June 14.  See United States v. Martinez, 922 F.2d 914, 921  (1st Cir. 1991) ("[D]efendants have an obligation to provide at least  some explanation of how the informant's testimony would have  supported their alleged defenses.").  We note that Gomez-Genao knew  who it was he had bragged to about the crime.  Santana was neither a  participant in the crime, nor an observer of it.  At most he was a  tipster.  When the informant is a tipster as opposed to a participant  in the crime, disclosure of the informant's identity when there is a  perceived threat is only required in exceptional circumstances under  which it is vital to a fair trial.  Lewis, 40 F.3d at 1335.  Gomez-Genao speculates that if he had known the identity earlier, he could  have hired an investigator.  The investigator might have come up with  something more, such as whether Santana and Gomez-Genao did eat lunch  together in the cafeteria where the bragging occurred.  That is not  enough.


7
Affirmed.



Notes:


*
  Of the Eastern District of Virginia, sitting by designation.


