5 Dead as Gunman Opens Fire in Manhattan Highrise; Shoots Self

Among the dead was Officer Didarul Islam, a 36-year-old NYPD officer.

- AGENCIES

A gunman armed with an assault-style rifle killed four people inside a Manhattan skyscraper that houses the headquarters of the NFL and offices of several major financial firms and then shot himself dead, New York City officials said on Monday.

The shooting took place at a skyscraper that is home to the headquarters of both the NFL and Blackstone, one of the world's largest investment firms, as well as other tenants.

The gunman, identified by authorities as Shane Tamura of Las Vegas, had a 'documented mental health history,' according to Police Commissioner Jessica Tisch, but his motive was still unknown.

"We are working to understand why he targeted this particular location," Tisch said.

The rampage happened at the end of the workday in the same part of Manhattan where the chief executive of UnitedHealthcare was gunned down outside a hotel late last year.