Turkish authorities have detained two people with alleged links to the outlawed Kurdistan Workers’ Party (PKK) on suspicion of having prior knowledge of the attack in Ankara that killed 97 people, officials said Wednesday.

The two are accused of knowing about the bombings in advance and sharing the information nine hours prior to the attack on Twitter, an official from the interior ministry said.

“This is a new investigation,” a Turkish government official told AFP. “We are questioning how they can have had advanced knowledge” of Saturday’s bombing.

The government said the individuals were affiliated with the PKK. Turkey has said the Islamic State extremist group is the prime suspect in the attack but said the involvement of other organisations like the PKK cannot be ruled out.