At that time, he told the court, "Rwanda went through a difficult time, with large scale arrests of opponents to the régime or their accomplices". The witness said Semanza took part in these arrests in Kigali Rurale prefecture where he was a mayor. Guichaoua said the situation was similar in all the prefectures "where people were asked to give the names of people to be arrested". The RPF launched an attack on Rwanda from Uganda on October 1st, 1990, and finally won a war against the former regime of president Juvénal Habyarimana in July 1994, ending the genocide. The genocide was sparked by the April 6th, 1994, downing of Habyarimana's 'plane which killed the president. "At that time, you had to know which side people were on," Guichaoua told the court. "An opposition had grown up, and there was political radicalism especially in the southern provinces of the country (…) and demands for multiparty politics. "This period also coincided with the birth of a new generation of militant politicians in Rwanda, the expert witness continued, and it was necessary for the central government to ensure itself of political supporters. He said Semanza belonged to that group of people who "acted without constraint to show that they supported the government", and that it was in that context that he proceeded with arrests and massacres in his commune so as to "stand out". Guichaoua said Semanza and those close to him acted on the premise that "an opportunity only comes around once, you have to take it or it is lost". According to the witness, Semanza seized the opportunity of the 1990 RPF attack to carve himself a place on the political map, notably through his contribution to the war effort. He also seized such an opportunity when the president's death was announced on April 6th, according to the witness. Guichaoua said Semanza was not happy about Habyarimana's death but that he thought he had to seize his own chance for political survival. This explained the massacres and other war crimes carried out by the accused after that date, Guichaoua told the court. Several witnesses have previously testified that Semanza's influence gave him the power during the genocide to order massacres of Tutsis and their "accomplices" or supervise the killings in certain regions. At that time he was no longer mayor of Bicumbi but had been nominated by Habyarimana's MRND party as an MP in the parliament to be set up under the 1993 Arusha peace accords. According to witnesses, he was influential in the MRND, especially in the communes of Bicumbi and Gikoro. Guichaoua told the court that previous witness testimonies of massacres carried out by Semanza in those places corroborated information that he had gathered himself, even if he was not an eyewitness to the events. Guichaoua was evacuated from Rwanda on April 11th, 1994, after arriving on April 4th for an assessment mission. His subsequent research was therefore based mostly on the testimonies of third parties. This trial is before Trial Chamber Three of the ICTR, composed of judges Yakov Ostrovsky of Russia (presiding), Lloyd George Williams of St. Kitts and Nevis and Pavel Dolenc of Slovenia. Semanza's trial is alternating before the Chamber with that of three suspects accused of genocide in the Cyangugu region of southwest Rwanda in 1994. Semanza is accused of 14 counts of genocide and crimes against humanity, including rape, for alleged crimes committed in Bicumbi and Gikoro in 1994. GA/AT/JC/PHD/FH (SE0424E)