Prosecutors say a Massachusetts man suspected of assaulting a woman went into a police station to try to collect a reward for offering a tip on the crime.

Middlesex District Attorney Marian Ryan's office says 31-year-old Kevin Suarez was arraigned Monday on charges of assault with intent to rape, and other offenses.

Police say the 18-year-old woman was walking in Lowell early Sunday when Suarez grabbed her from behind.

Police say the Methuen man repeatedly assaulted her before someone confronted him and interrupted the attack.

Capt. Timothy Crowley says Suarez walked into a station Monday to give a tip about the assault and receive a reward. He was arrested after questioning.

He is due in court Aug. 31 for a dangerousness hearing. His attorney couldn't immediately be reached for comment.