An eagle-eyed neighbor helped crack the bizarre case of a former NFL star now accused in a slew of attacks on women.

It was just after 2:30 p.m. June 7 when the Encinitas, Calif., resident spotted him: a hulking, muscled, 6-foot-4 stranger emerging from her 86-year-old neighbor’s mobile home.

He had no shirt on. And no reason to be there, she found when she confronted him.

“ ‘I’m just looking for my dog,’ ” she recalled him saying.

“I go, ‘What dog?’ and he said, ‘A red dog, Clifford.’ And I went, ‘There’s no dog here.’ ”

He hopped in a black SUV and left, but the woman called cops, who soon arrested a man near the trailer park on a burglary charge, according to a report.

It was Kellen Winslow Jr., once the highest-paid tight end in the league and the son of San Diego Chargers Hall of Famer Kellen Winslow Sr.

Winslow, whose publicist downplayed the arrest, posted bail the next day and was released. But prosecutors say the incident was a critical clue for authorities, who a week later charged Winslow Jr. in a string of sexual attacks from March to May 2018 on women in Encinitas, where he lives.

Winslow stands accused of targeting five women, ages 54 to 86, in charges including forcible sodomy, rape and kidnapping. If convicted, he could end up behind bars for the rest of his life.

His lawyer denied the allegations to The Post on Saturday.

“Of course not,” Brian Watkins said when asked if the charges were true. “He didn’t do these things.”

In two of the cases, police say, Winslow allegedly found his victims as they hitchhiked.

He drove the women to remote locations, where he raped them, according to police.

The first victim, age 54, was attacked on March 17.

Winslow Jr. “told her if she screamed, he would murder her,” San Diego County Deputy District Attorney Dan Owens told the San Diego Union-Tribune.

Another victim, 59, was sodomized, authorities said.

In a third incident, Winslow is accused of exposing himself to a 55-year-old woman gardening in her front yard. He was charged with burglary with intent to rape of both a 71-year-old woman and the 86-year-old in the Encinitas trailer park.

Winslow’s family is standing by him.

“On behalf of our son and my husband, we want to reiterate our love, support and affection for him during this difficult process,” his wife, Janelle, and father, Winslow Sr., said.

Winslow was drafted in 2004 and played 10 seasons in the NFL. He had a short stint with the New York Jets in 2013.