Parsons Green subway attack suspect charged by police

British police charged a teenager with attempted murder in connection to the Sept. 15 terror attack on a London subway train that injured at least 30 people.

Ahmed Hassan, 18, is accused of planting the homemade bomb that scorched train passengers. He was arrested Saturday at the port of Dover, a departure point for ferries to France.

Hassan was due in Westminster Magistrates Court later Friday. Three other men -- aged 17, 25 and 30 -- remained in custody but have not been charged with participating in the attack. At least one of those men had been staying at a "halfway house" for asylum seekers.

Hassan is believed to have stayed with fosters parents who were awarded an MBE for their work taking in hundreds of children and teens, including refugees, Sky News reported.

The Parsons Green attack sparked a huge hunt for the perpetrators and prompted officials to briefly raise the national terrorism threat to the highest level -- "critical."

The bomb partially detonated at the height of the morning rush hour. London police chief Cressida Dick said the bomb was packed with shrapnel and the carnage could have been "much worse."

The Associated Press contributed to this report.