Jakarta (CNN) A husband and wife used their four children in a string of deadly suicide attacks on three churches in the Indonesian city of Surabaya that left 12 people dead, according to the country's ranking police official.

The family included two daughters, aged 9 and 12 years old, said Head Gen. Tito Karnavian. The young girls were present when their mother detonated one of the bombs, and the couple's two teenage sons carried out a separate attack on another church.

Earlier reports indicated at least 10 people died in the Sunday morning attacks, but Karnavian said during a news conference that 12 victims were killed.

Forty-one people, including two police officers, were hospitalized with injuries, police spokesman Frans Barung Mangera said previously.

The six bombers also died, Karnavian said. Investigators believe the parents belong to Jamaah Ansharut Daulah, a terrorist group that lends its support to ISIS in Indonesia, the police general said.