NEW YORK CITY – Shocking new details have emerged following Monday’s deadly mass shooting in Midtown Manhattan, where four people — including an off-duty police officer — were gunned down inside a high-rise office building at 345 Park Avenue, home to the National Football League’s headquarters.
The alleged gunman, identified as 27-year-old Shane Tamura of Las Vegas, was found to be carrying a handwritten note in his pocket at the time of the incident, according to law enforcement sources speaking to ABC News. The note contained disturbing references to the NFL and an apparent claim that Tamura believed he was suffering from Chronic Traumatic Encephalopathy (CTE) — a degenerative brain disease linked to repeated head trauma. He also reportedly requested that his brain be studied after death.
The contents of the note have raised new questions about the gunman’s motivations and mental state in the lead-up to the horrifying act of violence that took place around 6:30 p.m. on Monday. Authorities have also confirmed that Tamura had a documented history of mental health issues and was known to have played high school football, adding weight to his self-diagnosed concerns about CTE.
The Attack
Police say Tamura entered the building armed with a rifle and opened fire without warning in the lobby area, where an off-duty NYPD officer working a private security detail was among the first struck. He died at the scene. Tamura then allegedly targeted civilians inside the building, fatally shooting three more individuals and injuring several others before turning the weapon on himself in what officials are describing as a murder-suicide.
First responders and heavily armed tactical units flooded the area as the situation unfolded, with frightened employees from nearby offices sheltering in place or being evacuated. Social media footage captured chaotic scenes outside the building, with Tamura seen approaching the structure calmly with the weapon in hand.
The victims’ names have not yet been officially released pending notification of next of kin, but authorities have confirmed that one NYPD officer and at least three civilians lost their lives. Multiple others remain hospitalized with injuries, some of them in critical condition.
The CTE Connection
In the note found on his body, Tamura reportedly blamed his deteriorating mental state on symptoms commonly associated with CTE, including confusion, paranoia, mood swings, and uncontrollable rage. CTE is a progressive brain condition that has been found in the brains of deceased football players, boxers, and military veterans — individuals who have sustained repeated head trauma over time.
While CTE cannot currently be diagnosed in living individuals with certainty, it has been increasingly recognized as a silent and devastating threat, particularly in contact sports. Symptoms often emerge years after the trauma and may include depression, cognitive impairment, aggression, and suicidal behavior.
Investigators are now working to verify whether Tamura had a history of concussions or documented brain injuries, and whether he ever sought medical help for his symptoms. The mention of the NFL in his note has prompted speculation that the location of the attack — a building known to house the NFL’s headquarters — may not have been random.
Community and Law Enforcement Response
“This was a horrific and calculated act of violence,” said NYPD Commissioner Edward Caban during a press conference Monday evening. “We lost one of our own — a police officer who was simply doing his job — and three innocent civilians whose lives were taken in an instant.”
New York Mayor Eric Adams also addressed the tragedy, expressing deep sorrow and vowing to increase mental health outreach and workplace security measures in the wake of the shooting. “We need to confront not only gun violence, but also the mental health crisis that is impacting cities across America,” Adams said.
The NYPD has asked for the public’s help in providing any additional video footage or eyewitness accounts of the incident. Authorities are continuing to investigate Tamura’s background, including any recent behavioral changes or communication that might offer insight into the motive behind the shooting.
National Implications
The shooting has reignited debate about the intersection of mental illness, traumatic brain injury, and gun access. It also brings renewed scrutiny to the long-standing concerns surrounding CTE and how it is addressed — or overlooked — in young athletes. Experts warn that while sports leagues have taken steps to reduce concussions, early detection and support for those showing potential symptoms remains inadequate.
Final Words
As the city grapples with the loss and begins to piece together the full scope of Monday’s tragedy, many are left wondering how a young man with apparent cries for help ended up unleashing such violence. The victims leave behind grieving families and communities shattered by a crime that may have roots not only in mental illness but in broader systemic issues involving healthcare, trauma, and prevention.
Anyone affected by the tragedy or in need of emotional support is encouraged to contact the NYC Well mental health hotline by calling 1-888-NYC-WELL. Those with information related to the investigation are urged to contact the NYPD or submit an anonymous tip to Crime Stoppers.
This story will be updated as more details emerge.
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