BOSTON — A Roxbury youth thought he could pull off a gunpoint robbery Thursday afternoon. Instead, police say, his victim turned the tables, disarmed him, and helped send him straight into custody.

The chaos began around 4:34 PM when Boston Police rushed to Zeigler Street after reports of a person with a gun. Officers from District B-2 spotted a group behind Bethune Way, but the suspects scattered. One youth clutched his waistband and leapt over a fence, sparking a chase that spilled out near Harrison Avenue.

Even as officers gave chase, another 911 call rang in from Ziegler Street — another man seen with a firearm. Cops confronted him as he reached for his backpack, ordering him to stop. He complied, and from his hoodie pocket they pulled out a loaded SCCY CPX-2 pistol, one round already chambered.

But police soon realized this wasn’t the robber — this was the victim. Investigators say the Roxbury youth had tried to stick him up at gunpoint, but the would-be target fought back, wrestled away the firearm, and held on until police arrived.

The alleged attacker, just 17 years old, was dragged into custody and slapped with a rap sheet that reads like a career criminal’s: armed robbery, assault with a dangerous weapon, assault and battery, resisting arrest, disorderly conduct, and illegal possession of both a firearm and ammunition.

He is expected to be arraigned in Boston Juvenile Court.

Neighbors were left rattled that a botched gunpoint robbery could erupt in broad daylight on a quiet street. Police, meanwhile, are calling it another reminder of how brazen Boston’s youth gun violence has become — and how quickly it can spiral out of control.