The two suspects were released early morning in Izmir, the source, who spoke on condition of anonymity due to restrictions on talking to the media, said.
Thursday’s attack occurred just outside a courthouse when police officer Fethi Sekin stopped a suspicious vehicle, which turned out to be carrying explosives.
The ensuing clash and a car-bomb attack left Sekin and a court official martyred and five others injured as a bigger blast involving another vehicle was thwarted, according to Governor Erol Ayyildiz.