A mass shooting at a high-rise office tower in Midtown Manhattan on Monday evening left four people dead and one seriously injured. New York police identified the shooter as Shane Devon Tamura, a 27-year-old man from Las Vegas with a history of mental illness. Tamura died from a self-inflicted gunshot wound on the 33rd floor of 345 Park Avenue, where he opened fire with an assault rifle.

Among the victims was 36-year-old off-duty New York police officer Didarul Islam. Originally from Bangladesh, Islam was assigned to a Bronx precinct and was a father of two with a third child on the way. New York Mayor Eric Adams praised his bravery, saying Islam “was saving lives” and died doing what he had sworn to do, to protect the public. Police Commissioner Jessica Tisch described him as a hero who “made the ultimate sacrifice.”

Also killed was Wesley LePatner, a senior executive at the investment firm Blackstone. She led the Core Plus real estate division and served as chief executive officer of the Blackstone Real Estate Income Trust. LePatner, a Yale graduate and former executive at Goldman Sachs, had joined Blackstone in 2014 and was widely respected within the firm and the broader financial industry.

A third victim, Julia Hyman, was identified on Tuesday. She was an associate at Rudin Management, which owns the building where the attack occurred. Hyman, a Cornell University graduate, was killed on the 33rd floor. The fourth victim is believed to be a security guard stationed in the building’s lobby, though authorities have not yet publicly released his name. A fifth individual, an employee of the National Football League, was gravely injured and remains hospitalized in stable condition.

Authorities recovered a handwritten note from Tamura’s wallet in which he claimed to suffer from chronic traumatic encephalopathy, or CTE, a neurodegenerative condition associated with repeated head trauma. Tamura attributed the disease to his years of playing football in high school and accused the National Football League of concealing the risks associated with the sport. The note reportedly included statements such as “Study my brain please,” “I am sorry,” and references to Terry Long, a former National Football League player diagnosed with CTE who died by suicide in 2005.

Mayor Adams stated that the shooter appeared to have been targeting the National Football League, which has corporate offices in the building, though Tamura entered the wrong elevator and ended up in Rudin Management’s offices instead. The National Football League has since increased security at its Park Avenue offices and encouraged staff to work remotely in the immediate aftermath of the attack.

Tamura, who had previously played as a varsity football player at Granada Hills Charter School in Los Angeles, reportedly struggled with mental health issues and had worked as a security guard in Las Vegas. A search of his vehicle uncovered a loaded revolver, ammunition, and prescription medication.

The shooting is being described as the deadliest mass shooting in New York City in more than two decades. The New York Police Department continues its investigation into the motive, with a focus on the shooter’s claims of brain injury and potential grievances against the National Football League.