They met in 2001 on a landscaping crew. From the start, Mark Geisenheyner seemed like trouble in work boots.

Geisenheyner, then 41, was enjoying a brief lull between stints in prison.

"I could tell he was a crazy maniac," said Gary Krobath, his coworker. "So I tried to distance myself from him."

Geisenheyner boasted to Krobath, 22 at the time, about his litany of crimes from burglary to parole violations.

If Krobath had been able to cut all ties to the career criminal, he might never have received Geisenheyner's phone call Sunday night. That call began a 17-hour ordeal that ended with a SWAT-team assault on Krobath's house and a murderer in the basement, lying in a halo of blood.

"He told me," Krobath said, "he was going to go down in a blaze of glory."

When the news broke late Saturday that five people had been shot in Montgomery County, Krobath didn't make the connection.

Paul and Monica Shay, a couple from New York, had been critically wounded. Shay's nephew, Joseph, was killed instantly, along with his girlfriend's 2-year-old son. The girlfriend, who called 911, was in critical condition.

"Mark had told me about this dude Paul," but never mentioned his last name, Krobath said.

He and Geisenheyner hadn't spoken in years until the spring of 2010, when they ran into each other in Pottstown. It turned out they were living a few blocks apart.

Geisenheyner tried to renew the friendship and confided in Krobath.

"I knew for the last 15 months he was going to rob this guy Paul," Krobath said. "He said he was going to kill him in front of his wife so that she would be scared and give him the money." Geisenheyner told Krobath that Shay owed him $230,000 for his part in an insurance scam.

Geisenheyner was to steal valuable paintings from Shay's house, then set it on fire. "Then Paul was going to claim the insurance. But the cops caught Mark with one of the paintings," Krobath said. "He got charged with receiving stolen property."

Geisenheyner said that he had been promised $300,000, but that Shay had paid only $70,000. Thus far, no information has emerged that would definitively rule out Geisenheyner's version of events.

Last summer, Krobath asked Geisenheyner for a favor. He was moving to Trainer and needed money to rent the moving van, and help hauling belongings. Geisenheyner pitched in, and that is how he knew where Krobath lived.

Twenty-four hours after the murders, Geisenheyner called Krobath and showed up shortly after.

"I want you to listen to something," he said, turning on a KYW-AM radio report about the murders.

"That was the dude Paul I told you about," Geisenheyner said, then laughed. "It went totally wrong. I was killing everybody."

"Dude, that's crazy," Krobath responded, afraid to say something wrong. Krobath tried to shake him off, saying he and his wife were leaving to see fireworks.

"I'll come, too," Geisenheyner said.

In the car, Krobath overheard Geisenheyner on the phone, arguing with a woman about the murders. Later, he would tell Krobath, "I think I got away with it," but the woman he'd been talking to was a problem. "Now," he said, "I gotta tie up some loose ends."

That was when Krobath decided to contact the police. When his wife went up to bed, he warned her they were in danger. Then he sat with Geisenheyner watching TV.

At 2:30 a.m., Krobath suggested, "I have a spare bedroom. Why don't you get some sleep? You need to have your mind together for tomorrow, to plan your next move."

Geisenheyner lay down in the second-floor guest room, under pink sheets and a purple-satin comforter.

When Krobath brought him a glass of water, Geisenheyner said, "If anything happens, grab your wife and get in a corner."

For the next two hours, Krobath, too scared that a phone call might be overheard, sent e-mails to news stations and law enforcement.

At 4:30, worried that time was running out, he tiptoed up to his sleeping wife and told her to run to the neighbor's house. Then he called 911.

The police dispatcher told him not to leave the house and urged him to speak louder. "Look!" Krobath said. "I've got the dude right here. I've got to whisper."

Krobath waited 20 minutes until two officers showed up, then he bolted.

After 45 minutes, the SWAT teams showed up.

About 11:30 a.m., when he was allowed back on the property, Krobath saw Geisenheyner's bloodied body in the backyard. "There was a bullet hole in his chest, maybe one in his head."

His gratitude to police for ending Geisenheyner's reign of violence is tempered by the devastation left behind.

Every window in his house is broken, the floors dusted with broken glass. The furniture has been overturned. Teargas canisters have pockmarked and burned the walls, and the acrid gas saturates the air, carpets, curtains, and clothing. The basement looks like a scene out of a snuff film. Blood has pooled in the corner where Geisenheyner hid behind the now-bullet-riddled dryer. A bloody trail to the back stairs marks where police dragged his body out.

"The house is unlivable," Krobath said. His landlord is holding him responsible for the cleanup.

"We have $60 to our name," he said, and the money that his wife makes cleaning houses and that he makes from construction won't cover the costs.

"I'll live, though, somehow, some way."

To watch an extended interview with Gary Krobath, go to www.philly.com/slayingEndText

Contact staff writer Melissa Dribben at 215-854-2590 or mdribben@phillynews.com.