Three men charged with placing backpack bombs on rush-hour commuter trains in Madrid denied having any role in the 2004 terror attacks, despite witness accounts that placed them on the convoys. The three were among 29 defendants now on trial for the massacre that killed 191 people and wounded more than 1,800 in Europe worst Islamic-linked terror attack. The trial, in its third day Monday, was expected to last at least five months. One of the three alleged bombers who testified Monday insisted his mother could vouch for him, saying he was in bed asleep when the bombs went off on March 11, 2004, and that she had fixed him breakfast. Another defendant said he had been at a restaurant miles (kilometers) away when the trains blew up. A third also denied taking part in the bombings, though he acknowledged having been friends with a Tunisian named as a radical Islamic ideologue behind the attacks and with other alleged ringleaders who, three weeks after the attacks, committed suicide to avoid arrest. Moroccan Jamal Zougam - who ran the shop that sold most of the cell phone cards used to set off the bombs - gave the day's first testimony, saying he had been implicated as punishment for having refused to be a police informant. Zougam, 33, said he was approached twice by Spanish police seeking help getting information about Islamic radicals, but he refused. He told the three-judge panel Monday that, following his detention two days after the bombings, an officer had visited his jail cell and told him he would not have been implicated if he had cooperated earlier with police. "He told me: 'If you had collaborated with us, this wouldn't have happened to you,"' Zougam said, testifying in the trial for a second day. "I realized it was revenge," he said. "I had nothing to do with this attack and with no other attack. I don't know why I'm in this trial." Zougam condemned the attacks, and denied he was a member of al-Qaida or any other radical Islamic group. "I live in Spain: This is like my country. Here, I live, I work, I eat," he said. Zougam said his mother had told the magistrate leading the investigation that he had been at home asleep when the bombs went off. Another alleged bomber, Syrian Basel Ghalyoun, acknowledged that he was a friend of Tunisian Serhan Ben Abdelmajid Fakhet and other ringleaders who blew themselves up as police moved to arrest them in the Madrid suburb of Leganes three weeks after the attacks, but denied having anything to do with the bombings. Ghalyoun, who continuously checked handwritten notes during the session and challenged the prosecutor and lawyers over certain facts and names, said he knew Fakhet was a radical. "Serhan considered the United States an enemy of the Muslim people," Ghalyoun said. The 26-year-old said he had told police that the Tunisian wanted to stage attacks in Spain, but said he was referring to attacks on banks and jewelry shops for money. He said police had urged him to used the generic word, attack. Moroccan Abdelmajid Bouchar, also placed by witnesses aboard one of the doomed trains, denied knowing any of the alleged cell members or having anything to do with the attacks. Bouchar denied investigators' claim that he had been with seven alleged ringleaders in the Leganes apartment before they committed suicide. He is said to have gone down to the street to empty the garbage, seen the police coming, screamed out to warn his colleagues and then taken off running - so fast police later nicknamed him "the deer." When asked by the prosecutor how he could explain the fact that traces of his DNA had been found on a date pit in the apartment, as well as his passport and other personal documents, he said: "I wasn't at that house and I don't know how these things got there."