PITTSBURGH - The random, stunning violence Tuesday evening in Collier, Pa., was incomprehensible to everyone - but one.

Over in seconds, the terror had been contemplated by the perpetrator for at least nine months.

In the end, police said, George Sodini fulfilled his self-described "exit plan" of carnage and suicide in an LA Fitness center, firing as many as 30 rounds from two handguns to kill three women and wound nine others, strangers all. He then used a third gun to fire a bullet into his head, killing himself. A fourth handgun was found in his pocket.

Daylight found survivors mourning lost loved ones, the wounded improving or clinging to life, detectives piecing together the tragedy, and a stunned community struggling with shock only months after the killing of three Pittsburgh police officers.

When he walked into the club just before 8 p.m., he carried two 9mm pistols with 30-round clips, a .45-caliber pistol, and a .32 semiautomatic in his pocket. He also had two extra 30-round clips in his gym bag.

Dressed in black pants and a black jacket and wearing a black headband, he walked into the exercise room where an aerobics class was being held and held the light switch down for 15 seconds. Police said someone at the club had previously shown him how to turn off the lights by holding the switch down that long.

With the lights out, he walked 10 feet into the room, dropped the gym bag, and started firing, emptying one 9mm, the shots splintering mirrors in the room. Fleeing women scattered, running to his side to get out of the glass doors.

Authorities said that Heidi Overmier, 46, of Carnegie, and Elizabeth Gannon, 49, of Green Tree, died at the scene. Jody Billingsley, 37, of Mount Lebanon, died at 8:52 p.m. at St. Clair Hospital.

Though anger and frustration over not being able to connect with women were reflected in writings he left behind, Sodini apparently did not know any of the women he targeted at the fitness club, said Allegheny County Police Superintendent Charles Moffatt.

"He had no relationship to anyone in the club that we know of," Moffatt said yesterday.

Among the most chilling developments yesterday was the discovery of Sodini's Web site, which included a diary that obliquely referred to his plan to randomly kill women and himself. The often rambling entries, beginning Nov. 5 and ending the night before the shootings, showed a man full of hopelessness, one who loathed women, religion, his family, blacks, coworkers, life, and, ultimately, himself.

Sodini, 48, of Scott Township outside Pittsburgh, was a systems analyst in the finance department of the law firm K&L Gates in downtown Pittsburgh. On his diary, he listed both his date of birth and date of death - 8-4-2009. It is unclear how long the blog had been on the Web.

"Why do this?? To young girls? Just read below," he began. "I kept a running log that includes my thoughts and actions, after I saw this project was going to drag on."

The "project," at times called the "exit plan," was discussed throughout the entries but was never explicitly explained, although it seemed clear suicide was part of it.

"Maybe soon, I will see God and Jesus," he wrote.

Police said they found documents containing rants similar to those in the blog.

Most of his writing bemoaned his lack of luck with women: "I actually look good. I dress good, am clean-shaven, bathe, touch of cologne yet 30 million women rejected me over an 18 or 25-year period. That is how I see it.

"A man needs a woman for confidence. He gets a boost on the job, career, with other men, and everywhere else when he knows inside he has someone to spend the night with and who is also a friend. This type of life I see is a closed world with me specifically and totally excluded."

Police said Sodini once belonged to a nondenominational church but stopped attending after an incident in 2006. The pastor told authorities Sodini had "overreached" with a woman in trying to gain her affections.

He said he hadn't had sex since 1990. Elsewhere he said he had fathered a child born in 1991 to a woman he hadn't seen since she was pregnant. The woman died five years ago, and family members said they knew nothing of Sodini's claim.

He wrote of being "isolated." An April 24 entry noted, "I guess this is when I take care of things. I don't have kids, close friends or anything. Just me here. If you have nothing, you have nothing to lose."

Bob J. Fox, 45, who lives across Orchard Spring Road from Sodini's house, was surprised to be mentioned on the shooter's Web postings. Sodini, with a hint of jealousy, claimed he saw an attractive woman leaving Fox's home in late July.

Fox said there was no hint of anger or violence visible in Sodini. He did not realize his neighbor had guns.

"There was nothing special about him," Fox said yesterday.

Candace Gettys, 58, Sodini's neighbor for 11 years, said that about two years ago he seemed to withdraw. She said that a couple of days ago she noticed that Sodini's yard and house were "unruly and messy looking. He usually kept it neat and mowed and kept up with things."

Sodini took pride in his appearance. On Saturday, he went to a tanning salon and purchased a $57 package for 10 more tanning sessions.

"We all thought he was a little square, kind of the class nerd," said Roberta Kozel, co-owner of Salon IAOMO. "We would joke, but he would never be mean or upset. I never saw any streak of madness."

In his diary, Sodini wrote about carrying out his "plan" at the "gym" but never identified it as LA Fitness, where he was a member.

Tuesday's attack was initially planned for January. On Jan. 5, he noted that the gym was crowded and "[T]omorrow should be good" for the "plan."

The next day: "It is 6:40 p.m., about hour and a half to go. God have mercy. I wish life could be better for all and the crazy world can somehow run smoother. I wish I had answers. Bye."

But then, he wrote: "It is 8:45 p.m. I chickened out! [Expletive]! I brought the loaded guns, everything. Hell!"

At the end of the diary, he wrote that "probably 99 percent of the people who know me well don't even think I was this crazy."

The diary ended bluntly: "Death Lives!"