A photo of a Boston police officer with his hand around a protester’s neck sparked outrage on the Internet and prompted an investigation by city officials yesterday.

A picture snapped by photographer Paul Weiskel during the Massachusetts Tea Party Coalition’s “Patriots Day Rally” on Sunday shows a Boston patrolman grabbing a masked individual by the throat. The alleged victim was part of a counterprotest.

“I was taking pictures of two kids in handcuffs and turned around to see this one cop with his hands around this kid’s neck,” Weiskel said, recalling Sunday’s rallies downtown.

The alleged victim was a member of one of several activist groups protesting the event.

“It looked like the cop just lost his temper and choked this one kid, turned on another kid, and pushed him back,” Weiskel said.

While Weiskel admits he didn’t see what sparked the confrontation, he said the “intense moment” ended quickly.

But according to Elaine Driscoll, spokeswoman for the Boston Police Department, protesters were “unruly and combative” and “attempted to aggressively interfere” with the Tea Party rally, which had a valid permit for the event.

“The aggressive nature of these individuals required officers to call for numerous additional units to respond,” she said. “As a matter of routine procedure following a day of aggressive protests, the department will review all of the activity that took place during the course of the day.”

Three counterprotesters were arrested at the event Sunday, according to reports.

What choked protester wrote on Facebook

“I’m holding was [sic] a wig I was wearing that a Tea Partier had just knocked off my head. I was asking the tea partier to explain to my [sic] why he thought it was okay to knock my wig off (‘My hand slipped,’ he replied sarcastically) when the officer came up and said something along the lines of ‘okay, take your sh** and get out of here’ and shoved me a few feet. I turned to him and said ‘Don’t push me.’ He replied ‘Don’t push you?!’ then did this.”