A Brooklyn man is facing murder charges in connection with a deadly shooting inside a Fort Greene diner over the weekend.

Investigators say Tyrone Gainer, 27, gunned down Jason Lewis, 34, early Sunday morning at the Country House Diner on Fulton Street.

A witness says Lewis tried to intervene in an argument between the gunman and his girlfriend.

"He's not a thug. He's a nine to five working guy. A family man. I guess he was at the wrong place at the wrong time," said Sam Woodey, a friend of the victim.

Lewis was rushed to Brooklyn Hospital where he died.

Gainer also faces weapons charges.