A New York City office building where a gunman killed four people then himself has reopened a week after the deadly shootings. On Monday, workers trickled back into 345 Park Avenue in Midtown Manhattan, a skyscraper home to high-profile tenants including the NFL and asset management firm Blackstone.

The New York City office building where a gunman fatally shot four people and himself reopened Monday, one week after the deadly rampage.Workers returned to 345 Park Ave., in Midtown Manhattan under the watchful eyes of NYPD officers and a surplus of additional security following the mass shooting.

The lobby of 345 Park Avenue reopened for the first time since last Monday's mass shooting that left four innocent victims dead.Monday marks one week since the tragedy and it isn't an easy day for employees who returned to work.

The Midtown Manhattan office building that was the scene of a deadly shooting reopens Monday, but under very different circumstances.