Nypd detectives are investigating “Jersey Shore” star Mike “The Situation” Sorrentino’s brother after a Manhattan woman accused him of holding her captive in a limo, law-enforcement sources said yesterday.

Kathryn Redino, 24, claims that on Oct. 20, she met Marc Sorrentino, 31, “The Situation” and three of their male friends at 1Oak nightclub on West 17th Street, the sources said. Redino says she joined them in a limo, which took them to an apartment on East 26th Street.

They then got back in the limo and headed to New Jersey, ignoring her pleas to be let out, she claims.

At one point. she claims, Marc Sorrentino broke a bottle and put it to her neck.

She said she escaped in Howell, NJ, and called 911.

Cops there issued Marc Sorrentino a summons for assault. “The Situation” was not charged.