"I'm absolutely shocked. I'm still trying to wrap my brain around it because from knowing this guy, it just doesn't make sense," said John Mincey, the suspect's former roommate.
Mincey rented a room to 23-year-old Paul Anthony Ciancia. They were roommates until February.
"He would always talk about documentaries he would watch about whatever, but there was never any kind of hatred, or any hatred group, or anything like that," said Mincey.
Mincey tells Eyewitness News that Ciancia had recently moved to Sun Valley, but they both had lunch as recently as last week.
"He said he was going back to New Jersey, going to work for his dad, making amends with family problems, and spending the holidays with his family. That's all I know," said Mincey.
The suspected gunman grew up in Pennsville, N.J. Authorities there were contacted Friday by family members who were concerned about Ciancia. The family told police Ciancia's younger brother received a text message from Ciancia indicating that he might do something to bring harm to himself. The family said they were concerned for Ciancia's well-being.
Pennsville Police Chief Allen Cummings is a longtime friend of Ciancia's father. Cummings said Pennsville police contacted the Los Angeles Police Department for a welfare check. The LAPD went to the apartment before the shooting and talked to Ciancia's roommates and reported back that everything was fine.
Federal agents and police also went to Mincey's apartment Friday afternoon.
"When detectives got here to investigate, I was completely shocked," said Mincey.
Not knowing the identity of the LAX shooting suspect at the time, the LAPD called Pennsville police to tell them everything appeared to be OK with Ciancia.
Ciancia graduated from high school in 2008. He was described by neighbors as a regular kid.
"I mean I know his family, and his parents, and his father. My heart just goes out to them," one man said.
The motive for the shooting remains under investigation. Law enforcement sources tell ABC News that authorities found a note at the scene that suggested the suspect was anti-government and that he expected to die in Friday's confrontation. The note ended with the letters "NWO," which law authorities believe refers to "New World Order."
Authorities also reportedly found a large amount of ammunition. Investigators believe the suspect acted alone, but they will investigate whether he has any ties to domestic terrorists.