Investigators don't believe the gunman, identified as 20-year-old Richard Shoop, intended to shoot anyone when he began firing at the ceiling and elsewhere at the Garden State Plaza in Paramus, about 15 miles northwest of New York City, shortly before the mall's closed Monday night. There were no other injuries.
"We think he went in with the intent that he was not going to come out alive," Bergen County Prosecutor John Molinelli said.
News of Shoop's suicide stunned friends and relatives. As recently as last week, Shoop had spoken about a potential new job and seemed especially happy about it, according to a woman who said she had known him since they were little.
"He told me that he was going to get a new job at this TV place and he was going to make good money," Madison Barbarini said. "He told me that he was doing really well and it seemed like he was really happy. Things just don't add up. Why would he do this? It doesn't make sense."
The friend she knew "honestly would never hurt a fly," Barbarini added.
The suspect's brother, Kevin Shoop, told reporters outside their home on a quiet suburban block in Teaneck that his brother was "a great person" who was liked by friends and family and gave no advance warning about what he intended to do.
"He just sadly decided to make an act of - an act of, I guess, self-indulgence - by taking his own life publicly," Kevin Shoop said. "And it's a tragedy to us all. And we're going to now handle matters and deal with them."
Dod Geges, the owner of a pizzeria in Teaneck where Shoop worked for several years, said Shoop didn't show violent tendencies and "was always sad" when he heard about shootings on TV.
Shoop left an ambiguous note with his family that raised concern, however. Molinelli would not call it a suicide note, but 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."
Gov. Chris Christie called the shooting a wakeup call for lawmakers to focus on mental health issues as part of a comprehensive effort to reduce gun violence.
"Obviously that young man went there to end his own life. We may not be that lucky next time," Christie said. "We need to get to the root causes of what drives a young man like that to drive to Garden State Plaza in that condition."
It is not known whether Shoop had any mental health issues. Authorities said he had a known drug problem.
Chaos erupted shortly before the mall's 9:30 p.m. closing time Monday 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 Richard Shoop's brother, who owned it legally and did not give the shooter permission to take it.
At the mall Monday night, witnesses said the sound of gunfire sent customers and employees rushing hysterically for the exits and hiding places at the mall, which remained closed Tuesday. Officials said the mall would reopen Wednesday morning.
Hundreds of law enforcement officers converged on the 2.2 million-square-foot mall, which was put on lockdown. New Jersey State Police landed a helicopter in the parking lot and SWAT teams with K-9 units initially went through the mall and started evacuating people.
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.
Lavoie reported from Boston. Associated Press writers Samantha Henry in Paramus, N.J.; David Porter in Mendham, N.J.; Mark Scolforo in Harrisburg, Pa.; and news researcher Rhonda Shafner in New York City contributed to this report.