A stranger broke into a Sunset Park home and nearly raped a 57-year-old woman, sparking fears of a new wave of sexual assaults in the Brooklyn neighborhood.

The creep rang the doorbell at the 57-year-old victim’s residence on 49th Street at about 3 a.m. Thursday, forced his way into her house and tried to rape her, cops said.

He groped the woman, but got spooked and fled when the victim’s brother walked in on the attack, police sources said.

The victim was taken to Coney Island Hospital for an evaluation yesterday, authorities said.

The suspect stands 5-foot-8, is in his 40s and weighs about 170 pounds, authorities said.

Cops are now investigating whether the Sunset Park incident is tied to a recent attack in nearby Park Slope — or worse, tied to a seven-month string of 20 attacks, including one rape, that plagued the area last year.

In the recent Park Slope attack, the assailant followed a 22-year-old woman and grabbed her from behind at around 5 a.m. Wednesday near 16th Street and Fourth Avenue. The sexual predator then fled.

Two cops who briefly detained the suspected groper but then released him were later put on modified duty, police sources said.

The suspect in that incident also believed to be in his 40s, though he is described as 5-foot-4 and 140 pounds.

Some neighbors said they heard about both incidents and are concerned about safety in the area.

“It’s very scary,” said Donna Rivera, 59. “I don’t go out late much, but I do worry about my kid.”

Another neighbor, Maria Sanchez, 55, said: “I thought this place was safe. But it’s not safe anywhere.”