A U.S. judge has dismissed all charges against an elderly immigrant accused of taking part in Rwanda's 1994 genocide.

The federal judge in Kansas Thursday granted a request by prosecutors to drop the case against Lazare Kobagaya.

In May, a jury in Wichita found the 84-year-old Kobagaya lied on immigration forms about where he was at the time of Rwanda's genocide, but said the U.S. government did not prove he took part in the atrocities.

Prosecutors said in their motion Thursday that they failed to disclose a witness whose testimony would have been favorable to the defense.

The move means that Kobagaya will not face further criminal charges on the count of lying or lose his U.S. citizenship.

During the trial, the prosecution argued that Kobagaya, an ethnic Hutu, ordered the killing of Tutsi neighbors in his Rwandan village of Birambo in 1994, and organized an attack at a nearby mountain that killed thousands of

fleeing Tutsis.

The defense had painted a different picture of Kobagaya, saying that during the genocide, he helped to save his wife, who is a Tutsi. Defense attorneys said Kobagaya was falsely accused by villagers who did take part in the killings and who received reduced sentences for claiming Kobagaya and others were involved in the genocide.

During Rwanda's 1994 genocide, extremist Hutus killed an estimated 800,000 Tutsis and moderate Hutus.