Shoop's body was found in Westfield Garden State Plaza mall at 3:20 a.m. Tuesday, hours after he fired at least six bullets without hurting anyone.
The shooting set off a frenzied hunt for the gunman in which officers where not sure whether he was still inside or outside the 2-million-square-foot building. Shoop reportedly shot himself after opening fire at the mall, and his body was found at an obscure location in the shopping center.
"We believe that he went in there with the intent to either be shot by police, which we call suicide by cop, or to take his own life, which ultimately he did," Bergen County Prosecutor John Molinelli said Tuesday morning.
Monday's shooting began around 9:20 p.m. ET, right before closing time. Shoop reportedly walked into the facility carrying a rifle modified to look like an AK-47. He was dressed in all black and wore a motorcycle helmet.
Molinelli said the gunman took the rifle from his brother.
According to witnesses' accounts the suspect had many chances to shoot and kill the people, but he never even tried. Instead, he fired toward the ceiling, an escalator, and elevator and a storefront.
"There were thousands of people in this mall at 9:20 tonight, and many of them were within 5 feet from him," Molinelli said. "He clearly had the ability to shoot an individual."
The 20-year-old gunman had a history of drug abuse known by local law enforcement.
"You wouldn't think that at age 20, how much can you do in your life, but in his life, he at least thought that he was reaching a point where there was no recourse but to take his own life," the prosecutor said.
Authorities believe Shoop acted alone. He reportedly left a note in the home where he was living though it is unclear why he went to the mall before he decided to take his own life.