NEW YORK: A shooting incident in Midtown Manhattan, New York, has left four people dead, including an off-duty police officer assigned to security duty, and five others seriously injured.

The 27-year-old gunman, wearing body armor and armed with a powerful M4 rifle, opened indiscriminate fire around 6:30 p.m. local time at a building located at 345 Park Avenue and 52nd Street.

According to ABC News, the building houses the headquarters of investment firm Blackstone and the National Football League (NFL). However, it is not yet clear whether the incident is directly connected to either of these companies or any other business operating in the building.

The suspected gunman, identified as Shane Devon Tamura, was later found dead, barricaded on approximately the 33rd floor of the building.

According to Police Commissioner Jessica Tisch, his death appears to be a suicide.

In a press conference Monday evening, Commissioner Tisch stated that preliminary investigations suggest Tamura had driven cross-country from Las Vegas to New York City before carrying out the attack.