Fear and confusion were rampant after a gunman shot and killed four people and wounded another in a Midtown Manhattan office tower Monday evening before, authorities said, taking his own life.

Officials said the gunman fatally shot himself after his attack, which set off a chaotic scene that rippled out into the heart of Manhattan during rush hour.

In a late-night press conference outside of NewYork-Presbyterian David H. Koch Center, police officials described the shooting, which shut down several blocks of Midtown Manhattan during Monday’s evening rush hour. They said the gunman acted alone and a motive was not yet clear.