Long Beach police say they arrested a 15-year-old robbery suspect after officers happened to see him holding up a man in downtown on Saturday.

Police said the officers were headed to an unrelated crime when they saw the robbery around 1:35 a.m. at Broadway and the Tribune Court alleyway, which is just west of The Promenade.

“During the robbery, a physical altercation occurred and the suspect fired the gun,” police said in a statement.

The teenage robber ran as officers arrived, but they quickly found him and the gun nearby, according to police.

Authorities said nobody was hurt.