Wichita ? The prosecution of an immigrant accused of participating in the 1994 Rwandan genocide has been dealt a major setback by a federal judge in Kansas.

U.S. District Judge Monti Belot again rejected a request from federal prosecutors Wednesday for more time to prepare for the trial of Lazare Kobagaya. The 85-year-old man is from the African nation of Burundi and lives in Topeka.

Kobagaya is charged with fraud and unlawfully obtaining U.S. citizenship in 2006. The government says the prosecution may be the first involving proof of genocide.

The Justice Department said Wednesday that authorities in a related Finnish case pending against Francois Bazaramba have restricted use of their evidence in the U.S. trial until August, when a formal indictment is expected to be charged in the case in that European nation.

“Complying with Finland’s request to delay dissemination of this evidence to the defendant until June 2009 and to the public at large until August 2009 further the government’s ability to work effectively with Finland in such matters in the future,” prosecutors wrote.

Documents filed in the U.S. case against Kobagaya allege he was a close friend of Bazaramba and helped lead in the 1994 attacks and killings of Tutsis.

Bazaramba has been held in Finnish police custody since April 2007 on suspicion of genocide, but has not been charged. Bazaramba allegedly led the Maraba unit of the MDR-Power, a Hutu extremist political party, according to court documents filed in Kansas.

Finland said in February it will not extradite Bazaramba to his home country because he might not receive a fair trial there. If charged, Bazaramba’s trial would be in Finland.

The Justice Ministry in Finland said its decision is based on a ruling by the International Criminal Tribunal that has prohibited the referral of three similar pending cases to Rwandan courts.

U.S. law generally requires that trial of a criminal matter begin within 70 days from the date on which an indictment is made public, although it allows the judge to exclude time from that speedy trial calculation for good cause. Kobagaya’s indictment was filed in January and unsealed last month.

The Justice Department asked for more time so it could use evidence gathered in the Finland case at trial in Kansas — particularly a statement from Bazaramba given to Finnish authorities, witness statements taken in Rwanda and items seized from Bazaramba’s Finnish home. The defense did not oppose the time extension.

But it took Belot just about an hour after their court filing to again deny the extension request from U.S. prosecutors, again without comment. He ordered attorneys to appear for a status conference on June 15 as previously scheduled. Kobagaya’s trial is set for June 23.

Justice Department spokesman Ian McCalab declined to comment on Belot’s ruling or the prosecution’s options now.

The Justice Department alleges in its indictment that Kobagaya lied during naturalization proceedings in Wichita by claiming he had lived in Burundi from 1993 to 1995. It contends he concealed that he had lived in Rwanda during the 1994 genocide and participated in the attacks and slaughter of hundreds of Tutsis.

An estimated 500,000 to 800,000 people were killed in Rwanda between April and July 1994. Most of the dead belonged to an ethnic group known as the Tutsi, while most of the killings were carried out by members of an ethnic group known as the Hutu.