Rwandan farmers stand along a river where fishermen saw floating corpses in sacks.
The general prosecutor of Burundi said on Tuesday that an investigation into 40 bodies found in a lake on the border with Rwanda has concluded that the dead were Rwandans, even though Rwanda has previously denied this.
The bodies, some wrapped in plastic, were discovered on the Burundian side of Lake Rweru in August. Their origin, who they were and how they died remains shrouded in mystery. No credible theories have been offered either by officials or local media.
Initially officials from the two east African countries concluded that the bodies had not come from their respective countries.
But Burundi's general prosecutor, Valentin Bagorikunda, said on Tuesday that officials had examined the site where the bodies were found and interviewed those present when they washed up on shore.
"In conclusion, following all the evidence we have, it appears that the bodies found in August came from Rwanda," he told a news conference. "This is corroborated by reports from Burundi security forces, and testimonies of farmers and fishermen from Rwanda and Burundi."
A Rwandan official could not immediately be reached to respond to the comments.
Since the genocide of 1994 in Rwanda, President Paul Kagame has won Western praise for rebuilding the country but he has also been criticised for intolerance of political opposition.
Politically troubled Burundi has endured decades of ethnic massacres that worsened during a 12-year civil war that ended in 2005.Last month, the United States called on the both countries to conduct a "prompt, thorough, impartial and concerted investigation" into the deaths