Investigators are combing through evidence in the wake of New York City’s deadliest mass shooting since 2000, trying to figure out more about the gunman who unleashed an assault-style rifle in Midtown,

Four people — including two Jewish women — were killed during a mass shooting at 345 Park Avenue in Midtown Manhattan on Monday. The gunman, 27-year-old Shane Tamura of Las Vegas, entered the lobby with an assault rifle and opened fire before killing himself on the 33rd floor. Authorities say he may have been targeting the NFL offices.

The gunman who killed four people in a midtown Manhattan office building left a suicide note indicating that he was targeting the NFL, police said.