Egypt's Interior Ministry yesterday identified four men it accused of training a bomber who killed himself and three tourists here on April 7. A ministry statement said the teenage bomber, Hassan Rafaat Ahmed Bashandi, "was affiliated with an extremist group that included four members" who trained and recruited him. Three of the suspects are in custody. A fourth remains at large, the ministry said. The group also prepared the explosives that detonated near the Khan El-Khalili bazaar, a historic part of Cairo popular with tourists.Bashandi, who was 17 or 18 years old, was attempting to plant the bomb — a concoction of TNT placed in a nail-filled leather bag — when it exploded prematurely, killing himself, an American and two French tourists. It was unclear when the three suspects were arrested. Last week, an investigator said Bashandi was aided by three others, but didn't elaborate. Police arrested 30 people after identifying the bomber, including his mother and 19 relatives. His mother has since been released.