PARAMUS, N.J. — A 20-year-old gunman intent on dying fired multiple shots inside New Jersey’s largest shopping mall, trapping hundreds of customers and employees for hours as police scoured stores for the shooter, who was found dead early Tuesday of a self-inflicted wound, authorities said. There were no other injuries.

Investigators don’t believe the gunman, identified as 20-year-old Richard Shoop of Teaneck, intended to shoot anyone when he began firing at the ceiling and elsewhere at the Garden State Plaza on Monday night shortly before the mall’s closing time, Bergen County Prosecutor John Molinelli said.

“We think he went in with the intent that he was not going to come out alive,” Molinelli said.

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.”

A phone message left at a Shoop residence in Teaneck was not immediately returned.

Chaos erupted shortly before the mall’s 9:30 p.m. closing time when authorities said a man dressed in black and wearing a motorcycle helmet fired six shots. Molinelli said the gun, which was modified to look like an AK-47 assault rifle, belonged to Shoop’s brother, who owned it legally and did not give his brother permission to take it.

Shoop’s body was discovered around 3:20 a.m. Tuesday 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 investigators were still trying to determine why he went there.