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.

A man carrying a rifle killed four people at a New York City office tower Monday, including an off-duty New York City police officer, and wounded a fifth before taking his own life