The witness is known only as "DDM 12 "and is 46-years-old.
Before Judge Andre Denis, he narrated the circumstances which led him to leave Rwanda and seek asylum in Quebec, Canada
"I had received threats", he claimed, adding that a Rwandan man threatened him with serious consequences if he testified for the accused. The threats were made in Kigali on 20 October 2007, he told the Court.
"This Rwandan man (whose identity was not revealed) said that I have been contacted to testify in the trial of Munyaneza. If it is true, there will be consequences ", the witness said.
The witness said he took the threats seriously and benefited from a meeting at the United Nations Headquarters in New York, to come to Montreal on 15 November.
Since then, he said, he was working on procedures to seek for an asylum in Canada.
The witness told the court that he considered the defendant "as a friend" whom he met regularly, since their first meeting in 1986.
The two men had not seen each other since their last meeting in Butare, southern Rwanda, in July 1994.
Under the gaze of Mr Munyaneza and chains tied to his feet, the witness did not always seem at ease during the cross-examination by Mrs Pascale Ledoux, Crown Prosecutor.
Earlier, prosecution witnesses had accused Mr Munyaneza of having directed militia armed with machetes and clubs, supervised a network of road blocks in Butare, which led to killings of thousands of ethnic Tutsis.
Mrs Ledoux requested on several occasions that DDM 12 specify his role in the killings.
The witness claimed that he never saw dead bodies; neither controlled Tutsis, nor even heard shots when he was on guard at road blocks.
"One can describe me as an Interahamwe [militiaman], because I was at the barricade", he said, adding: "It was an obligation. If you disobeyed you will be killed immediately. You will be accused of complicity ".
The testimonies will continue for next six weeks.
The court moves to Rwanda from 14 April to 9 May and later to Tanzania from 19 to 30 May.
© Hirondelle News Agency