LYNNWOOD — The investigation into a robbery at an Edmonds apartment complex in May has led to an arrest in the 2011 attack of an Edmonds Community College student.

Detectives believe the same man is responsible for both crimes, according to reports filed Friday by Lynnwood police.

The man, 23, of Edmonds, was booked into jail May 22. Edmonds police alleged that he robbed a woman at gunpoint on May 15 as she got out of her car in a parking lot.

The man’s ex-girlfriend reportedly told Edmonds detectives that he committed the robbery because he needed money for heroin. She also said he had committed another robbery years ago at Edmonds Community College when he was “dope sick.”

On May 31, 2011, a student at the college was stabbed, pepper-sprayed and robbed in a bathroom. The student, then 22, struggled with the attacker, who also was armed with a box-cutter.

Police shared a suspect sketch with the public, but the investigation stalled due to a lack of information.

Edmonds police interviewed the ex-girlfriend about the parking lot robbery when she shared details about the college robbery, records show. The woman reportedly knew details about the college robbery that hadn’t been made public.

Edmonds and Lynnwood police have been working together in their investigations. The community college is within Lynnwood city limits.

The victim in the college attack since has moved to Texas. He reportedly identified the Edmonds man as his attacker from a photo montage.

The suspect reportedly told detectives he was joking when he confessed to the 2011 robbery to his ex-girlfriend, according to police reports.

He faces charges for first-degree robbery in both cases.

Rikki King: 425-339-3449; rking@heraldnet.com