The man who plunged a knife into a Bronx straphanger’s back may have gone berserk because he wrongly believed the victim snapped a photo of him, cops and the injured guy said Monday.

The 33-year-old victim, Leo Frasier, told WABC he was on the escalator at the 161 St-Yankee Stadium subway station around 1:30 p.m. Sunday when the assailant stabbed him.

Frasier said that before the attack, he complained to the suspect that the man was standing too close to him.

“I had to let him know, like, ‘Excuse me, young man, get out of my personal space. I’ve had a long day. It’s hot,’ ” Frasier told the outlet.

He said his attacker was then waiting for him at the end of the escalator and stabbed him possibly because the suspect thought he’d taken his picture, not to mention that Frasier is gay.

“[Bystanders] said, ‘He’s bleeding, he’s bleeding,’ so I felt massive blood coming out of my back,” Frasier said from his hospital bed.”

The victim said the blade barely missed his lung.

“I guess, you know whatever, he could tell I was gay,” Frasier said. “I don’t give a damn, but at the end of the day, like, this became a hate crime.”

Cops said they could not say whether the attack was a hate crime.

Frasier was taken to Lincoln Medical Center, where he was listed in stable condition.

Footage released Sunday shows the shirtless suspect, wearing multi-colored shorts, fleeing down the escalator.

He remained at large Monday.