Police Believe the Manhattan Shooter Was Targeting NFL Offices — Details on Shane Tamura

A photograph of a man calmly walking through Midtown Manhattan, while carrying a high-powered rifle, is circulating online. What makes this image even more haunting is the fact that it happened while the sun was still up, as life carried on around him. He is seen walking purposefully towards an office building while people in the background, seemingly unaware of what's happening, are going about their day as usual.

Police have identified the suspect as 27-year-old Shane Tamura, a resident of Las Vegas. He drove from Nevada to New York, leaving Saturday, July 26, and arriving that Monday. Two hours later, he allegedly opened fire in an office, leaving four dead and one injured.

Who is Shane Tamura? Here's what we know.

Investigators are still piecing together information about Tamura, who died of a self-inflicted gunshot wound. A motive has yet to be established, but Tamura left a note in which he blamed his alleged actions and mental illness on chronic traumatic encephalopathy (CTE), reports ABC News.

According to the Mayo Clinic, CTE is a brain disease likely associated with multiple head injuries. This has been found in the brains of people who play football or other contact sports.

Although Tamura played football in high school in Los Angeles, he never played professionally. Police have not found evidence that Tamura was ever diagnosed with CTE, which is difficult to do in a living person.

In his letter, Tamura accused the NFL of concealing how dangerous the sport is to players' brains, claiming they did so to increase profits. The NFL's headquarters were in the building Tamura allegedly targeted, but he chose the wrong elevator bank and got off on a different floor.

Tamura's struggles with mental health date back to 2022, when he had his first Mental Health Crisis Hold in Nevada. Two years later, there was another. A hold typically lasts 72 hours while mental health professionals determine if a person is a danger to themselves or others. In Nevada, the law states that Tamura would have been brought to the hospital by police. In 2022, the 27-year-old also got his concealed carry license. He also had a previous arrest for trespassing.

In a press conference, Police Commissioner Jessica Tisch said 36-year-old Didarul Islam was "doing what he does best," which was save lives, reported NBC News. Islam, a father of two with a third on the way, was killed during the Manhattan shooting.

"He put himself in harm’s way," said Commissioner Tisch. "He made the ultimate sacrifice — shot in cold blood, wearing a uniform that stood for the promise that he made to this city."

Blackstone executive Wesley LePatner was also one of the victims. The CEO of Blackstone Real Estate Income Trust was a "beloved member of the family," said the company in a statement. "She was brilliant, passionate, warm, generous, and deeply respected within our firm and beyond."

The names of the three other victims, two of whom are deceased, have not been released. NFL Commissioner Roger Goodell revealed that one of the NFL's employees was injured in the attack.

"He is currently in the hospital and in stable condition," said Goodell.