New York City police detectives searched a studio apartment in Las Vegas that belonged to the suspected gunman in Monday's mass shooting at a Midtown Manhattan.

The gunman who shot and killed four people at a midtown Manhattan building Monday before killing himself bought the murder weapon for $1,400 from his boss at the Las Vegas casino where he worked security, NYPD officials said Wednesday.

A gunman who killed four people at a Manhattan office building bought the rifle from his supervisor at a Las Vegas casino, authorities said.