Two bombs rocked the Athens court complex on Evelpidon Street in the pre-dawn hours yesterday, slightly injuring a police officer. Security officials expressed fear that the blast by a previously unheard-of group could signal a return to domestic urban guerrilla activity. They said attackers had aimed to kill police. The first homemade time bomb went off at 2.47 a.m. A more powerful one exploded at 3.05 a.m., slightly injuring a police officer in the legs. He was 40 meters away. There was no warning. Later, someone saying he represented Revolutionary Struggle (Epanastatikos Agonas) claimed responsibility in a call to the Eleftherotypia newspaper. The attack was the most significant since the collapse of November 17, Greece’s deadliest terrorist group, last summer. Nineteen defendants are on trial in a specially built courtroom in Korydallos Prison, many kilometers away from the site of yesterday’s attack. Alleged N17 mastermind Alexandros Yotopoulos began testifying on Thursday and continued yesterday. «The location and timing of the bombs show that the incident was most likely tied to the trial and Yotopoulos’s testimony,» a senior police official told Kathimerini. «They wanted to kill policemen.» Police and judicial officials believe the attackers aimed to show that despite the N17 trial and the impending trial of alleged leaders of the Revolutionary Popular Struggle (ELA), there are still people like them on the loose and capable of carrying out attacks. Officials had expressed the belief that they were in control of the situation. With security a priority for the Athens Olympics, security services are expected to push hard to solve the case. An initial investigation suggested that the bombs were put together using techniques used by terrorist groups in the past, suggesting that an old hand may be working with new operatives. The part of the court complex that was damaged is not guarded by police and the attackers appear to have eluded revolving surveillance cameras. In Thessaloniki at 1.30 a.m. yesterday, unidentified attackers threw two gasoline bombs at a Eurobank branch, causing damage.