"The murders were a purposeful and conscious effort to be a grand, powerful man of the moment. He couldn't achieve that through social means, like having a career or girlfriend, so he did by becoming a killer," said Berrill.
Sodini, who had been employed since 1999 as a systems analyst at the Pittsburgh law firm K&L Gates, writes of his inability to meet or connect with women, despite wanting to desperately.
He said he had not had a girlfriend since 1984. In one instance he says he has no children, but later claims another woman, Lee Ann Valdiserri, had his baby in 1991. Public records indicate Valdiserri died in 2004.
"I guess some of us were simply meant to walk a lonely path. I have slept alone for over 20 years. Last time I slept all night with a girlfriend it was 1982. Proof I am a total malfunction. Girls and women don't even give me a second look ANYWHERE. There is something BLATANTLY wrong with me that NO god dam person will tell me what it is," he wrote on his blog.
Sodini writes that he had previously planned the shooting for January but "chickened out."
He complains about feeling neglected and bullied by his mother and older brother, a classic grievance for high-profile murderers, said Garrett.
Sodini refers to his mother as the "central boss" and calls her "vindictive" and "very dominant."
He describes his brother Michael Sodini, as a "big bully, twice the size of most others."
Calls by ABC News.com to Sodini's mother Jean and brother Michael were not answered.
ABC News's Emily Friedman contributed to this report.