New York City police detectives searched a studio apartment in Las Vegas that belonged to the suspected gunman in Monday's mass shooting at a Midtown Manhattan.

When I look into you and dad’s eyes, all I see is disappointment,” Tamura wrote to his mother in the note. “I love you, Momma. I’m sorry.”

Shane Tamura, 27, who fatally shot four people in the building that houses the National Football League's headquarters Monday, said in a suicide note that he had chronic traumatic encephalopathy, known at CTE,