A Syosset man arrested after posing as a federal air marshal and being found with guns in his car and in his home pleaded guilty Wednesday to multiple felony weapons charges, prosecutors said.

Mark Vicars, 50, pleaded guilty before Supreme Court Justice William Donnino to three counts of second-degree criminal possession of a weapon and one count of second-degree criminal possession of a forged instrument, according to prosecutors.

Nassau County District Attorney Madeline Singas said prosecutors will recommend a 15-year prison sentence. Vicars returns to court March 3.

“This defendant masqueraded as a federal air marshal for years and possessed an incredibly dangerous arsenal of weapons that included handguns, an assault weapon and more than 8,300 rounds of ammunition,” Singas said. “Thankfully, this defendant’s ridiculous farce came to end when our partners in law enforcement, based on a tip, arrested him and discovered his stockpile of illegal weapons.”

His attorney, Dennis Lemke of Mineola, could not be reacehd for comment.

Police said they had gotten a tip and had Vicars under surveillance when they made a traffic stop of his car on Jericho Turnpike in December 2015.

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Vicars activated the police-style emergency lights on the dashboard of his 2014 Dodge Durango as he pulled over, police said.

Prosecutors said Vicars “produced a fraudulent shield and credentials that identified him as a federal air marshal.”

A loaded assault rifle, a loaded pistol, a knife, a tactical vest with high-capacity magazines and body armor were found in the car, according to police.

Officers armed with a search warrant went to his home on The Knoll, where they recovered the other handguns and “8,300 assorted rounds of assault ammunition,” Nassau police Det. Lt. Richard LeBrun said at the time.

LeBrun said Vicars had no known terrorist connections.