"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.