NEWTOWN, Conn.—In stockpiling ammunition, smashing his computers and killing his mother as she slept, Adam Lanza undertook considerable preparation before shooting up an elementary school on Friday, a former FBI profiler said.
"He didn't just snap. This takes a lot of planning," said Mary Ellen O'Toole, who worked for 15 years in the FBI's Behavioral Analysis Unit where she studied psychopaths and helped capture killers.
O'Toole retired in 2009 and has no direct connection to the case.
Investigators had hoped Lanza's computers would shed some light on what caused him to massacre 20 first-graders and six adults at Sandy Hook Elementary, a school he once attended. But the 20-year-old reportedly butchered his computer's hard drives with a hammer or screwdriver, according to ABC News.
Still, the FBI's Computer Analysis and Response Team has been working around the clock on the case and could make progress despite the damage.
"The FBI is pretty good, we can pull stuff off anything," O'Toole said.
O'Toole still assists law enforcement and has written a book titled "Dangerous Instincts." She says the Sandy Hook shootings are worse than any case she has dealt with before.
"I have not seen a case with callousness of this extreme," O'Toole said of Lanza's shooting rampage. "It's off the charts."
Multiple reports have painted Lanza, who lived alone with his divorced mother, as being socially awkward but very intelligent, especially when it came to computers.
O'Toole said the way Lanza carried out his killings suggested a high measure of control, including damaging the computers.
"His computers were very important to him. They were a window to his world," O'Toole told Yahoo News. "He didn't want them to survive. He knew that they would give insight into him and didn't want people to have it."
Friends and family of Lanza's mother, 52-year-old Nancy Lanza, have said she dedicated her life to helping her son, who reportedly had Asperger's syndrome or other medical issues.
O'Toole said people with Asperger's, which is a neurological disorder, aren't known to commit such violence and that too much is being made about Lanza's mental health.
"It's time we stop putting out the mental health issue as an excuse that he didn't know what he was doing," she said.
Lanza brought three guns into the school, all owned by his mother. He killed his victims with a high-powered semi-automatic rifle, but he also carried two pistols, one of which he used to take his own life. Police say he sprayed hundreds of bullets inside the school and had considerably more left over to use.
Shooting his mother while she slept and preloading numerous rounds of ammunition into the gun clips signals that Lanza was on a mission, O'Toole said.
"He wanted to accomplish maximum lethality," O'Toole said. "He was not out of touch with reality. I think he put some security measures in place so he wouldn't be stopped."
Which unfortunately meant choosing the most helpless of victims, she added.
"If you pick older people you are going to have some blowback," O'Toole said. "He didn't want people to interfere. When people take security measures like that, you know what you are doing is wrong."