Julio José López, a retired construction worker who was a key witness in the trial against former police chief Miguel Etchecolatz, has been missing since September 17. The case in which he testified was one of the first trials held since the Supreme Court struck down its amnesty laws [IJT-53-50-28]. Despite the fact that the city's walls are covered with posters of López and the fact that he has made newspaper headlines and television prime time, López is still missing without a trace. On October 6, tens of thousands of people marched to the seat of the government chanting "We want the truth. We want justice. We want Julio back." The more than 200 police officers investigating the disappearance of López have come up empty-handed after following up on tips phoned in to a toll free number. López's disappearance has also been accompanied by a barrage of threats to judges, prosecutors and witnesses in human rights cases and on October 5, a demonstration by some 3,000 friends and relatives of soldiers on trial was organized in order to demand a national plebiscite to reinstate the amnesty laws. The idea was quickly rebuffed by president Nestor Kirchner, who has encouraged the Dirty War trials and has made human rights a cornerstone of his domestic policy. After the demonstration, President Kirchner ordered the arrest of six officers who took part in the event dressed in uniform without authorization from their superior. The government has set up a special witness protection program for human rights victims, and stepped up security measures for judges and prosecutors involved in the trials. López, who had already "gone missing" between 1976 and 1979, testified against 62 military and police officers. Only seven are in jail so far. "Less than 5% of those indicted are under arrest," said Nilda Eloy, another key witness in the Etchecolatz trial. "The other 95% are free, and we are in danger."