NYPD department head Terence Monahan posted a clip of the incident on Twitter, showing the man entering the station and waving a large knife.
You can see the man entering the lobby, where he is met by an agent who immediately notices the knife in his left hand.
The man, identified as 28-year-old Starlin Lopez, suffers from an unidentified mental illness, said his sister Luary Lopez in an interview with WCBS-TV.
Lopez told police inside the station that the government interfered with his life and said he wanted to die, police said.
The video shows several agents circling Lopez, then charging him and putting him in custody.
Lopez was taken to a hospital following the incident. The police said he told the paramedics: "I'm too old to kill myself," when asked if he was suicidal.
