EDMONTON - Every lie an amateur filmmaker told in the tumultuous weeks before and after he killed and cut up a total stranger were thrown back at him Thursday at his murder trial.

Mark Twitchell acknowledged on the witness stand that he lied to friends, family, his wife, his mistress, the victim, the victim's friends, a potential victim, street police officers, detectives and even to a random cop who stopped him for a speeding ticket.

Some lies were simple. Some were elaborate. Some took days to construct, he testified, while others were concocted on the spur of the moment.

Twitchell, who is charged with the first-degree murder of Johnny Altinger, has admitted that he killed him, but testified that he did it in self-defence when a publicity stunt went wrong.

At one point during Thursday's cross-examination, Twitchell even critiqued his acting when telling his lies.

"I'm surprised someone would buy that," he told court as the packed gallery watched a large-screen video of a police interrogation of Twitchell shortly after Altinger disappeared Oct. 10, 2008.

On the video, Twitchell appears shocked when he learns Altinger has disappeared after telling friends he was heading to a garage Twitchell had rented on Edmonton's south side.

Twitchell pounds the table when the detective says someone might have been using the garage without Twitchell knowing.

"A lot of that was overacted," Twitchell told the six-man, six-woman jury. "My answers were too quick coming on the heels of the questions."

Twitchell, 31, is accused of luring Altinger to the garage that night, knocking him senseless with a copper pipe, knifing him to death, cutting up the body parts and dumping them down a sewer.

The Crown says a 42-page file found on Twitchell's computer was his diary and provides a motive. It begins: "This is the story of my progression into becoming a serial killer."

It vividly details the author's attack on a man named Jim in the garage. It then details the dissection of the body.

The writer describes cutting the body into "medallion-sized portions," and compares it to carving a turkey or "spilling the guts" of a Halloween pumpkin.

The meat is shaved from the bones, he writes, the nose carved off and the eyes cut out. The author marvels at the victim's brain and the roundness of the buttocks, but in the end gets back to business.

"Meat is meat," he writes.

Twitchell has said the document was a work of fiction he hoped to market as a novel. He said names had been changed, but the characters represented real people in his life. The work is based on true events, but there is a heavy layering of fiction, including the reference to the author wanting to become a serial killer, he said.

He also said the killing of the Jim character does not reflect what happened to Altinger.

He has told court that he lured Altinger -- as well as another stranger a week earlier -- to the garage to get them to play along with a publicity stunt he had come up with to help sell his latest movie.

Court has heard that two weeks before Altinger died, Twitchell and his buddies shot an eight-minute slasher movie in the garage. The plot is about a man lured to a remote location on an Internet date, knifed to death and dismembered.

Twitchell said after they made the movie, his "savant power" kicked in and he thought of a way to hype it.

The plan, he told Crown prosecutor Avril Inglis, was to lure strangers to the garage that had been dressed up like a "kill room" -- with knives, a table to cut up corpses and plastic sheets on the walls and floor to catch the blood.

Once the strangers arrived, he planned to tell them they'd been tricked and that there was no Internet date. He would then ask them to blog about the experience as if they really had been terrorized. This, he hoped, would create a buzz about the movie.

Court has heard that a week before Altinger died, Gilles Tetreault was lured to the garage for an Internet date. He told court he was attacked by a man in a hockey mask, fought back and fled, but didn't go to police.

The following week, Twitchell said he lured Altinger to the garage, but this time told him about the prank.

Altinger, he said, became enraged. The two fought and Twitchell knifed him to death in self-defence. He said he cut up the body, disposed of it and continued to spin lies because no one would believe it was an accident.

He admitted that he went to Altinger's home, broke into his computer and sent emails to Altinger's friends telling them not to worry, that the 38-year-old single man had run off to Costa Rica with a woman named Jen.

"I've got a one-way ticket to heaven and I'm not coming back," Twitchell wrote to them, pretending to be Altinger.

"You wrote that about the man who died in front of you several days earlier," said Inglis.

Twitchell's voice dropped and tears welled in his eyes.

"Yes, I did," he whispered.