Nevada's gun laws are again under scrutiny after a Las Vegas man opened fire in Midtown Manhattan, killing four people and injuring another.

Investigators discovered a second note at the Las Vegas home of the gunman who killed four people in midtown Manhattan, officials said. The note mirrors the one found on his body in New York, where he blamed football for his mental illness as authorities examine his brain for signs of CTE.

Shane Tamura is suspected of killing four people before shooting himself on the 33rd floor of the building at 345 Park Avenue, authorities said.