ATLANTA - After nearly three years investigating a courthouse gunman's bizarre break out scheme, prosecutors are walking away from the case without charging anyone, despite evidence the shooter's pen pal-turned girlfriend paid off a jail guard.

Brian Nichols' elaborate plot included sawing through cinder block walls, fleeing on Thanksgiving Day because the guards would be sluggish from feasting and leaving a faux breadcrumb trail to throw off authorities, according to investigative documents reviewed by The Associated Press. The scheming involved at least four people - a pen pal who became his girlfriend, a deputy at the jail, a paralegal who worked on his case and Nichols' brother.

The Georgia Bureau of Investigation, whose agents spent countless hours investigating, closed the case Wednesday. The file, which included thousands of pages reviewed by the AP, noted that prosecutors chose not to press charges.

Nichols' girlfriend, Lisa Meneguzzo, played a key role in the plot, coming up with cash, writing letters to Nichols and doing research for him, according to the document. Fulton County prosecutors granted her immunity in return for her cooperation, preventing her from being charged.

The deputy, David Ramsey, admitted accepting at least $100 from Nichols' girlfriend and used money she sent one of his friends to buy a DVD player, according to the documents. But he told authorities he took the money to keep Nichols' cell phone charged and to buy the inmate snacks from a vending machine, not to help in the escape. He told them he thought Meneguzzo was "crazy."

Ramsey resigned in June 2006, about the time investigators were tipped off by an inmate about Nichols' plot and his cell was searched. The circumstances of why Ramsey stepped down were unclear.

Layla Zon, the special prosecutor designated to handle the case, didn't immediately comment, but apparently didn't have enough evidence to charge the paralegal, Tamela Hysten, or Nichols' brother, Mark.

Meneguzzo also said Hysten smuggled letters out of the prison for Brian Nichols, and that she paid the paralegal $500 to deliver Nichols a book about escape and to bring him a device made by his brother that would help cut through the walls, the report said.

Meneguzzo declined to comment Wednesday. Ramsey did not return repeated phone calls, and a phone number for Mark Nichols was disconnected. Hysten also didn't return a telephone call, but her attorney previously said she did nothing wrong.

Hundreds of manpower hours were used to investigate the case, and the investigation came as prosecutors were already taking heat for a $3 million taxpayer funded defense for Nichols, who escaped from custody in March 2005 at the Fulton County Courthouse and killed a judge, a court reporter, a sheriff's deputy and, later, a federal agent.

Nichols started plotting his escape from jail a couple of months later. Meneguzzo, of Beacon Falls, Conn., contacted Nichols shortly after the courthouse rampage and he wrote back in flirty notes that mention his favorite foods and his desire to be with her. Soon, he was telling her "morale among the guards here" was low because they were not being paid well, and that he could use that as leverage to help.

Soon, she managed to smuggle in a cellphone, according to the documents, and gave Ramsey a charger to keep the phone juiced.

Nichols also instructed his girlfriend to call a concrete company and ask how to cut a hole in a cinder block wall, and she told investigators she met with the jail guard in her hotel room. Ramsey sketched a map of the jail, including a list of walls that couldn't be penetrated and told her to take pictures of the facility to help Nichols escape, according to the documents.

Nichols, who was facing the death penalty, was undaunted by the task of escaping.

"You know my thoughts about the impossible, it's only an excuse for lack of initiative and ambition," Nichols wrote to his girlfriend in June 2005. "It's going to be a challenge, but we must stand firm in our resolution while adjusting to the dynamics of the cards of life we have been dealt."

Nichols also wanted his brother to go to the hiking and biking Silver Comet Trail in west Georgia and leave hot sauce packets and a brown bag lunch with Nichols' name on it to throw police off. He asked Meneguzzo to buy a white cargo van, emblazoned with the Red Cross emblem.

In a June 2006 letter to her, he talked of hiding in the boxes in the back of the van.

"I'll have at least a 9-hour head start, and should be able to make it to at least Kentucky, maybe Ohio" before police are aware, he wrote.

He aimed to escape on Thanksgiving, when guards "will be full from all that food, since it's a holiday there will be skeleton staff." If his brother got caught helping, Nichols thought he wouldn't mind.

"It's really a win-win situation all the way around because if something goes wrong and he gets caught, the most he will do is 5 yrs aiding and abetting a fugitive and he'll have the opportunity for book and movie deals out the wazoo. In fact, after I get out, he could admit that he helped me and get book and movie deals out the wazoo."

After Meneguzzo expressed concern, Nichols wrote her a June 2005 note addressed to "Lisa Nichols" that tried to calm her.

"But really, to stand against tyranny and oppression is the responsibility of the righteous and you should be commended," he wrote. "You are doing the right thing, never forget that."

Trudy Brandau, the sister of court reporter Nichols gunned down, said she considers the case closed and was glad there are no more prosecutions.

"The thought of bringing anything about that back up is disturbing in itself," she said. "We don't want to have to relive any of this. It's unfortunate how the whole case came down, and the end result was wrong. But I feel like life could be too short and I don't want to dwell on it."