The gunman who opened fire on people exercising at a Pittsburgh gym had for months been targeting the Latin dance class he burst into, killing three women and himself, police said Wednesday.

George Sodini, 48, had a schedule from the LA Fitness center at his residence with the "Latin impact" dance aerobics times marked.

"He targeted this aerobics class," said Allegheny County police Superintendent Charles Moffatt. "He had this class circled on a schedule in his home."

But oddly, Sodini had no relationship with any of the women he gunned down during the Tuesday night rampage that left three dead and nine injured before Sodini committed suicide.

"He just had this hatred of women," Moffatt told reporters Wednesday. "He was full of hatred."

The three who died were Heidi Overmier, 46, of Carnegie; Elizabeth Gannon, 49, of Pittsburgh; and Jody Billingsley, 38, of Mount Lebanon.

Sodini, of Scott Township, Pa., burst into the fitness club wearing a black headband and clothes. He was at the gym twice on Tuesday before returning at night to carry out the 8:15 p.m. shootings.

Sodini was carrying four guns and used three in the massacre, according to Moffatt. He fired at least 36 shots during the attack.

Earlier Wednesday, disturbing details emerged of the gunman's mental state. A blog attributed to him revealed that he hated women, had been planning the rampage for months and "chickened out" during an earlier attempt in January.

In the rambling online journal posted under his name, Sodini wrote about how he was sick of being rejected by women, and that he hadn't had sex for almost 20 years.

He ended by writing, "Death Lives!" The blog was removed from the Internet Wednesday.

RAW DATA: Excerpts from the gunman's blog.

PHOTOS: Gunman Opens Fire on Pittsburgh Gym

In his diary, Sodini spoke of his struggles with alcoholism and listed his date of death as Aug. 4, 2009, the day of the massacre.

He listed his status as "Never married," and he characterized himself as a depressed loner with no way out of his misery other than death. Neighbors described Sodini as antisocial.

"The biggest problem of all is not having relationships or friends, but not being able to achieve and acquire what I desire in those or many other areas," said an entry dated Sunday. "Everthing (sic) stays the same regardless of the effert (sic) I put in. If I had control over my life then I would be happier. But for about the past 30 years, I have not."

The 4,610-word Web page, on a domain registered in Sodini's name, appeared to be a nine-month chronology of his plans to commit the shooting, his decision to delay it and the process that led to the eventual carnage at the health club Tuesday.

Authorities did not immediately confirm that the site belonged to Sodini, but the elaborate nature of the comments so soon after the shootings suggested authenticity.

The Web site's author wrote of planning the attack since at least November, and had tried to do it when the same Tuesday-night dance aerobics class he targeted met on Jan. 6.

"It is 8:45PM: I chickened out!" he wrote. "I brought the loaded guns, everything. Hell!"

Sodini walked into the LA Fitness center in Collier Township, Pa., Tuesday night, entered the class and placed a duffel bag on the ground. After pausing a few moments, he took guns out of the bag and started shooting, witnesses told police.

"He walked right into the room where the shootings occurred as if he knew exactly where he was going," Moffatt said earlier Wednesday. "I think he went in with the idea of doing what he did."

The violence rocked the suburban Pittsburgh town of about 5,300 residents some eight miles southwest of downtown Pittsburgh.

Joann Gazzam, a member of the weekly dance aerobics class, saw the gunman walk to the back of the room near some weights, set down a bag and fumble with it for a few minutes before coming up with what appeared to be two guns and opening fire, according to her sister, Debi Wozniak, of suburban Dormont.

Gazzam told Wozniak that the instructor was among those who appeared to have been shot, and that the gunman had killed himself.

"She told me, 'Debi, I seen everything. Oh, my God, I seen everything. I seen him pull out the guns,"' said Wozniak, who usually attends the class every Tuesday from 8 p.m. to 9 p.m. but was running late and didn't make it.

The clean-shaven gunman walked in the room wearing workout gear, turned off the lights and, at first nobody knew what was happening, said Stacey Falk, 26, of Bridgeville, who was in the class.

"All of us girls were just ducking behind each other and it was just, you know, I was behind a girl, one of the girls in front to get hit, and when he was in the opposite corner shooting, I booked it," she told WPXI-TV.

Five of the wounded victims arrived in critical condition at UPMC Mercy Hospital, but three of them were upgraded to serious condition by early Wednesday. Two women remained in fair condition at another Pittsburgh hospital. One victim was treated and released for a shoulder wound and a woman with a bullet wound to the knee remained in stable condition Wednesday.

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The Associated Press contributed to this report.