Red marks the spot!

An eagle-eyed Boston motorist spotting red smoke wafting out of a woman’s hoodie pocket as she ran down the street Wednesday just after 11 a.m. jumped into action making a citizen arrest, police report.

“The bystander recounted that while traveling down Boston St toward Andrew Station, he noticed the suspect running from (a) bank parking lot with red smoke emitting from her hooded sweatshirt pocket. Pursuing her down Dorchester Ave and onto Father Songin Way, the bystander apprehended the suspect and alerted a nearby Sergeant,” BPD said in a release this morning.

Now that’s a Hub driver with his radar up!

Officers from District C-6 (South Boston) arrested Miriam Dealmeida, 38, of Boston, following an unarmed bank robbery, police said.

Police were already responding to a bank alarm at 501 Southampton St.

“The suspect, described as a white female, approximately 5′ tall, wearing a black thin hoodie with the hood covering her head, blue jeans, and a white disposable surgical mask, fled in an unknown direction,” police said.

“Broadcasting the suspect’s description, officers scoured the area, and a courageous bystander flagged them down on Father Songin Way, where he was restraining a woman matching the suspect’s description,” police added.

The hero bystander was not identified, but he sure was quick on the draw.

Dealmeida is charged with Unarmed Bank Robbery, with further charges anticipated for a separate bank robbery earlier that day at 68 Kneeland St, East West Bank. She is expected to appear for arraignment at South Boston District Court.