New York- The heartless mugger who gunned down a stunning actress on the lower East Side was caught on tape by a security camera just minutes before the killing, police sources said yesterday.

The surveillance tape, released yesterday by NYPD detectives, shows a man wearing a white hooded sweatshirt, a white scarf and white pants walking down Clinton St. with a gang of four other men and two women in bulky winter clothes.

None of their faces is shown, and NYPD investigators officially said the people caught on the tape have not yet been labeled suspects.

But police sources told the Daily News that the man dressed mostly in white was believed to be the cold-blooded killer.

Less than 10 minutes after the video was shot, the young man allegedly fired a bullet into the chest of 28-year-old Nicole duFresne, the sources said.

The tape does not capture the violence, but it gives cops Рand New Yorkers Рtheir first look at the mugger who allegedly killed duFresne because she dared to confront him for beating her fianc̩ in the trendy neighborhood.

“I hope the people who are involved in this turn themselves in,” said fiancé Jeffrey Sparks, 29. “I haven’t seen the tape but I hope that it helps the police find who did this.”

The break in the case was revealed as stunning new details of the killing emerged.

Scott Nath, who was walking with his girlfriend, Sparks and duFresne when the mugger attacked them around 3 a.m. Thursday, said duFresne was furious after the thug pistol-whipped her fiancé.

“Nicole was coming up angry and ready to kick some ass,” said Nath, a 32-year-old actor, who had been drinking with his three friends at the popular bar Max Fish before the attack. “I don’t know what she said. Not ‘Bring it on,’ but ‘What are you f—–g doing!’ ” Nath recalled tearfully.

Sparks said his passionate wife-to-be uttered the fatal words: “What do you think you are doing? What are you going to do, shoot us?” as the mugger waved a chrome pistol at her and her pal, Mary Jane Gibson.

“He took a shot at Mary Jane, but there was no bullet,” said Sparks. “The gun didn’t go off.”

But the next pull of the trigger sent a round into duFresne’s chest and the gunman and his pals fleeing.

DuFresne, who hours earlier had finished working her first shift as a waitress at the Rockwood Music Hall on Allen St., died at Beth Israel Medical Center.

Sparks and Nath said the gang acted confused at times.

“There were two other people there. They weren’t attacking us, but they were there in the way,” Nath said. “They were apologizing for him, in a way, but not stopping him.”

Nath said he had seen the surveillance tape and that the same gang attacked him and his friends.

Sparks said while duFresne was furious at her killer, she wouldn’t want him put to death. “She would want the focus to be less about a black kid and a gun and more about a culture where a kid can get a gun,” Sparks said after picking out a dress for duFresne to wear when she is cremated.

DuFresne’s grieving mother said her daughter, who had survived a vicious rape at Emerson College, was not one to let her loved ones get hurt.

“She was fiercely protective. When her fiancé went down, she would stand up for him,” said Linda duFresne after arriving from Minnesota to claim her daughter’s body. “She stood up to him.”

But a police source said Nicole duFresne would have been wiser to back away. “She was a girl from Minnesota, talking back to a ghetto guy who was ignorant enough to think it was a challenge,” the source said.

A police source said the same gunman and his posse apparently were responsible for attacking a 22-year-old man only an hour earlier in the same neighborhood.

Around 2 a.m., a thug approached the man at Clinton and Delancey Sts. and demanded his jacket. When the man refused, the attacker pistol-whipped him, and his accomplices started punching him, but the victim managed to escape, cops said. The victim later identified his assailant as the man in the white scarf on the surveillance tape, the source said.

Cops canvassed the neighborhood after the attack, but didn’t find the suspects, sources said.

The videotape of duFresne’s alleged killer was recorded by an outdoor security camera at Schiller’s Liquor Bar, a Rivington St. eatery close to where she was shot outside 84 Clinton St.