Cops caught a suspect Saturday in the murder of Karina ­Vetrano, the beautiful jogger whose brutal strangulation last summer — in the high weeds of Spring Creek Park in Queens — had transfixed the city.

Officials did not immediately release the name of the suspect, but sources told The Post he is in his 20s and lives in a housing project in East New York, Brooklyn, a neighborhood just west of her home in Howard Beach.

The suspect had been on police radar for a while, sources told The Post.

Some time ago, an off-duty cop saw him acting suspiciously somewhere in Howard Beach, and called the local precinct.

The suspect was questioned at that time but police found no valid reason to hold him and he was released without charges.

Earlier this past week, investigators approached him again.

They asked him for a DNA sample, which he gave voluntarily — thereby potentially sealing his own fate, sources said.

He had no prior record, so until he agreed to a cheek swab, his DNA profile had been unknown to law enforcement, sources told The Post.

Investigators had found the DNA of Vetrano’s suspected attacker on her phone, neck and fingernails, sources told The Post.

He was taken into custody and questioned Saturday night in a precinct outside Howard Beach, sources also said.

Vetrano, 30, had been jogging in the park when she was raped, bludgeoned and strangled last Aug. 2.

This past Thursday marked six months since Karina’s murder.

Her father, Philip, a retired firefighter, had been tireless in asking police and the media to keep his daughter’s investigation alive during months of little progress.

Karina lived with her parents, and the father and daughter had been frequent jogging partners.

But Philip had not joined her in the early evening of Aug. 2 when she donned black shorts and a jogging top and left home for what would be her final time.

Instead, he later joined the search party that scoured the park after she failed to return home — and he was the one who found her body.

Police believe Karina was ­ambushed and dragged into the marshes.

She fought back bravely as her killer overpowered her, punching her in the mouth hard enough to dislodge a tooth.

“She had stems of weeds in her hands,” NYPD Chief of Detectives Robert Boyce had told reporters.

“She fought not to go into those weeds,” he said.

Additional reporting by Tina Moore