Hours after the attacks , the Chief of the Indonesian National Police Tito Karnavian , stated in a news conference that Jamaah Ansharut Daulah , a local branch of the Islamic State , was the group who was responsible for perpetrating the attacks . The group was responsible for the previous church bombing in Samarinda in 2016 and was also blamed for a series of attacks against the Indonesian police in 2016 and 2017
church bombing in Samarinda
2016 Samarinda church bombing
Surabaya bombings