Authorities believe a man who fired multiple shots inside New Jersey's largest shopping centre, and was found dead of a self-inflicted wound, did not want to hurt anyone.
Investigators do not believe Richard Shoop, 20, intended to shoot anyone when he began firing at the ceiling and elsewhere at the Garden State Plaza shortly before the mall's closing time on Monday night.
Bergen County prosecutor John Molinelli said: "We think he went in with the intent that he was not going to come out alive."
He said Shoop was known to authorities and had had a problem with drugs, but he did not elaborate.
The prosecutor said Shoop left an ambiguous note with his family. While Molinelli would not call it a suicide note, he said it did "express that an end is coming. It could have been prison. ... It could have been what he did last night. It gave his family reason to reach out to us".
Shoop's body was discovered at around 3.20am in a back corridor of the mall, deep within a lower level, in an area that is not accessible to the public, Paramus Police Chief Kenneth Ehrenberg said.
Shoop did not work at the mall, he said, and police are still trying to determine why he went there.
Authorities said a man dressed in black and wearing a motorcycle helmet fired shots shortly before the mall's 9.30pm closing time.
Molinelli said the weapon, which was modified to look like an AK-47, belonged to Shoop's brother, who owned it legally.
Witnesses said the sound of gunfire sent customers and employees rushing for the mall's exits.
Hundreds of police officers converged on the mall, which was put on lockdown. New Jersey State Police landed a helicopter in the car park and SWAT teams went through the mall and evacuated anyone who was still inside.
The mall, which has more than 270 stores, is located in Bergen County, about 15 miles (25km) north-west of Manhattan.