Sri Lankan police are holding a Syrian national in custody for questioning over the Easter Sunday attacks on churches and hotels, three government and military sources told Reuters on Tuesday.

“The terrorist investigation division of the police arrested a Syrian national following the attacks for interrogation,” a source said. Two other officials with knowledge of the investigation confirmed the detention.

“He was arrested after interrogation of local suspects,” a second source said.

No group has yet to claim responsibility for Easter Sunday’s suicide bomb attacks on three churches and four luxury hotels that killed 290 people and wounded about 500 people.