TEANECK - Law enforcement officials and people who knew Richard Shoop are trying to piece together what may have motivated him to open fire at the Garden State Plaza mall last night.

Shoop, 20, opened fire at the Garden State Plaza mall last night before taking his own life.

Authorities raided Shoop's Teaneck home at around 1 a.m. Investigators remained at the home throughout the morning.

Shoop's brother, Kevin, made a brief statement to the media outside saying that the incident came as a shock to the family and the community. He called the shooting sporadic and said no one saw it coming.

Bergen County Prosecutor John Molinelli says Shoop used his brother's rifle when he opened fire inside the crowded Garden State Plaza mall Monday night.

"My brother intended to harm nobody but himself," says Kevin Shoop. "He took an act of self-indulgence by taking his own life publicly. It's a tragedy to us all."

Authorities say Richard Shoop had been involved with drug possession and drug dealing, but it's not clear whether that played a role in his behavior.

The body of the 20-year-old was found in a back area of the mall in Paramus at around 3:30 a.m. There were no other injuries.

Shoop graduated from Teaneck High School in 2011 and worked in a local pizzeria.