SEATTLE (AP) — A 14-year-old boy who was spray painting a Seattle building was struck and Johnathan Walkerkilled by the Seattle Center Monorail on Sunday night, according to police.

Officers responded just before 9 p.m. to reports that a person had been hit by the monorail near the intersection of Fifth Avenue and Denny Way, the Seattle Police Department said in a post on its website.

Officers found the teen unresponsive, police said, and he died despite lifesaving measures by Seattle fire personnel. His name hasn’t been released.

The teen had been spray painting a building next to the monorail tracks before he was hit, according to video reviewed by police.

An investigation is ongoing.

The monorail was out of service Sunday night and resumed service Monday.