A New York police officer, a “beloved” security guard, a young Cornell graduate and a senior executive with investment firm Blackstone were killed Monday when a lone gunman stormed a sprawling office tower in Midtown Manhattan and opened fire.

The shooter, identified as 27-year-old Shane Tamura of Las Vegas, left a suicide note suggesting he had CTE and was targeting the NFL headquarters, officials say.

The Manhattan office building shooting victims include NYPD Officer Didarul Islam, Blackstone executive Wesley LePatner and security guard Aland Etienne.