A lawyer says Kenyan police have arrested a man and three teenagers over a weekend explosion at a bus stop that killed six people.
Mbugua Mureithi said Monday that police arrested Sylvester Opiyo and three teens on Sunday. Opiyo turned himself in to police in December after authorities said he was wanted. He was then released without charge.
Mureithi said police are arresting "the usual suspects" and it was unclear what evidence linked Opiyo to the attack.
Police did not answer calls seeking comment.
The police have said they are investigating whether the Saturday night grenade attack was linked to Somalia's al-Qaida-linked al-Shabab militia. Al-Shabab sympathizers have carried out several attacks since Kenyan troops moved into Somalia in October.
(This version CORRECTS APNewsNow. Corrects misspelled word in headline.)