According to Suffolk County Police, Frank Panebianco and his girlfriend, Jessica Kasten, both 28 years old, were out with friends Sunday night at the Long Island Pour House on Patchogue Road.
Relatives say Panebianco and Kasten had been dating for no more than six months. They arrived at the restaurant Sunday night to have dinner and watch a football game.
They were joined by their friend Jack Schneider and a friend of his.
Police say what they did not know is that Ms. Kasten's ex-boyfriend Michael Skiadas had followed them there, and was circling the parking lot outside.
As the couple and their friends enjoyed dinner, he continued to circle the lot.
When the four left the restaurant, he was waiting outside with a shotgun.
They walked out at approximately 11:20 p.m. and were confronted in the parking lot by Skiadas.
An argument ensued and Skiadas took a shotgun from his Jeep, which was parked nearby, police say.
A friend, Jack Schneider, attempted to calm down Skiadas and Skiadas struck him in the head with the shotgun.
Investigators say Kasten and Panebianco attempted to drive away north on Patchogue Road when Skiadas ran toward their car and fired two shots from the shotgun, striking Panebianco in the torso.
Skiadas then returned to his vehicle and committed suicide by shooting himself. He was pronounced dead at the scene.
Panebianco, of Mount Sinai, and Schneider, 32, were transported to Stony Brook University Hospital where Panebianco was pronounced dead.
Schneider was treated for non-life threatening injuries.
Kasten, of Lloyd Harbor, was not injured.
Panebianco's family tells Eyewitness News that he did not know the man who killed him.
Police say the killer lived in a tiny cottage in Nesconset where neighbors said they hardly knew him.