The New York City office building that was the site of a mass shooting Monday had significant security measures in place.

Four people were killed and a fifth was injured in a mass shooting at a Midtown Manhattan office building on Monday.The injured victim was an employee at the NFL, according to NFL Commissioner Roger Goodell.

The four victims who were shot and killed by a gunman inside a Midtown Manhattan office building on Monday night have been identified.They include two women — a Blackstone executive and a Cornell graduate — and two security guards,

The man who killed four people in the New York City skyscraper that is home to NFL headquarters carried a note blaming the league for his mental health problems

The gunman who opened fire in midtown Manhattan on Monday, killing four people before turning the gun on himself, left a note mentioning “CTE” several times, officials familiar with the investigation told NBC News.