The gunman who opened fire on an exercise class in a suburban Pittsburgh fitness center, killing three people and himself, hated women, had been planning his attack for months and "chickened out" during an earlier attempt, he wrote in a blog.

In a rambling online journal posted under his name, George Sodini, 48, of Scott Township, Pa., wrote about his hatred of women and how he was sick of being rejected by them. He said he hadn't had sex for almost 20 years.

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

Sodini killed three women and injured nine others before he turned his gun on himself and committed suicide. Police say he may have fired as many as 52 shots during his rampage.

RAW DATA: Excerpts from the gunman's blog.

PHOTOS: Gunman Opens Fire on Pittsburgh Gym

Sodini walked into the LA Fitness center in Collier Township, Pa., Tuesday night, entered a "Latin impact" dance aerobics class and placed a duffel bag on the ground. After pausing a few moments, he took at least two guns out of the bag and started shooting.

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

Authorities on Wednesday identified the gunman as Sodini. The three women who died were Heidi Overmier, 46, of Carnegie; Elizabeth Gannon, 49, of Pittsburgh; and Jody Billingsley, 38, of Mount Lebanon.

In his diary, Sodini spoke of his struggles with alcoholism and listed his date of death as Aug. 4, 2009, the date 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 stays the same regardless of the effert 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!"

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 ever Tuesday from 8 p.m. to 9 p.m. but was running late and didn't make it. Police say the shooting happened about 8:15 p.m.

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.

The gunman went into the health club planning to shoot several people — firing "multiple" weapons "indiscriminately" — and didn't say anything before unleashing a burst of bullets, Moffatt said.

Moffatt said police recovered at least two guns from the scene and a note from the shooter's duffel bag, but he would not say who wrote it.

"I don't think anyone could have stopped him," Moffatt said.

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.

Loretta Moss, 44, of McDonald, said she was exercising on a treadmill when she heard a popping noise.

"I didn't pay any attention, and the next minute, people were screaming," said Moss, who had come to the gym Tuesday night for the first time in a couple of weeks. She said she then heard more pops.

"There was like a whole spray of them. I'd say about 15 altogether, and then people started screaming and yelling and started running out the building," she said.

"We laid down, and then after the last set of ... gunshots, we got up, and someone said, 'run."'

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The Associated Press contributed to this report.