It was late at night and a group of Jewish teenagers were on a walk around the Chestnut Hill Reservoir in Massachusetts.

Boston College Police Officer Carl Mascioli was on patrol on May 17, the night that the four teens saved a man with an anti-Semitic tattoo in Chestnut Hill.

"As I approached them, two of them ran up to my car," said the patrolman. "There was a body in the water."

Mascioli ran down the embankment and found a man partially submerged and not moving.

"While I was pulling him out of the water, I also observed that he had a swastika on his hand," Mascioli said.

It turned out the man the Jewish boys helped save had a tattoo of the Nazi symbol, and Mascioli told them about it.

"I kind of let the gentlemen know sometimes some deeds have a funny way of turning around," said the officer. "Their good deed had a little bit of a twist to it."

The students, who study at a nearby Yeshiva high school in Brighton, were not permitted to speak with NBC10 Boston about the incident, but they had a message for the officer to share with the man they helped rescue.

"They wanted just to let him know that it was four young Jewish boys that helped save his life," recalled Mascioli, who said the students had no regrets about helping a man with an anti-Semitic tattoo. "A good deed is a good deed and that's part of life. We should be helping everybody out."

It's unknown how the man ended up in the water. But police say he didn't have much time left, and if it hadn't been for the teenagers, the patrolman likely wouldn't have seen him.

The man is expected to recover.