Mark Twitchell told an Edmonton jury Wednesday he killed Johnny Altinger in self-defence.

The 31-year-old is accused of bludgeoning, stabbing and dismembering Altinger, 38, on Oct. 10, 2008 at a rented garage in south Edmonton. He spent the entire day on the stand Wednesday, testifying in his own defence at his first-degree murder trial.

The Crown maintains that Twitchell, an aspiring filmmaker, lured Altinger to a rented garage in south Edmonton by posing as a woman on an online dating site with the sole purpose of killing him.

Twitchell admitted he was trying to lure men but it wasn't to kill them.

It was all part of a new entertainment concept involving making a movie and writing a book followed by an online component. The whole idea is to "keep the audience down the rabbit hole, staying in the fantasy world as long as possible."

The men would help him create an urban legend that would create buzz for his film House of Cards, about a Dexter-like serial killer.

After luring his first victim, Gilles Tetreault, Twitchell decided terrifying Tetreault would be "ridiculously effective" in creating hype, he said.

When Tetreault arrived, Twitchell rushed him. "I used the stun baton mainly to scare him," he said. 

Earlier Tetreault had testified he was attacked and beaten at the garage and barely managed to escape with his life.

One week after Tetreault escaped, Altinger was lured to the garage for a meeting that would end in Atlinger's death.

Twitchell and Altinger struggled

"For two and a half years I've been trying to figure out where the crossed wires were," Twitchell told the courtroom.

When Altinger arrived at the garage, Twitchell revealed his plan to him, but Altinger didn't like it, he said. Altinger became angry when he learned the whole thing was a hoax.

After the two exchanged insults, Twitchell turned his back on Altinger, he said.

That’s when he felt a blow to his back, Twitchell said. He grabbed a pipe and swung at Altinger.

"I kept hitting him in the head," Twitchell said, "because he was pulling me forward."

As the struggle continued, Twitchell swung harder and harder — a "mangled mess of swings," he said.

When Altinger, bleeding profusely, grabbed the pipe, Twitchell reached for his knife.

When he saw his knife sticking in Altinger, he froze and staggered back, he said.

He pondered what to do next.

"There was this war in my head between screaming out 'Call 911' and then 'How bad does this look? Take a look around. Look at what this place looks like,'" he testified.

Twitchell's voice began to quaver as he recounted dismembering the body. After a "quick haphazard" cleanup, his wife called, asking him to pick up baby formula on the way home.

On Tuesday, police detectives testified that in June 2010 Twitchell gave them a Google map leading them to the sewer where they found Altinger's remains.

"I wanted to give [Altinger's] family and friends that closure," he testified.

Admitted to writing SKconfessions

Twitchell was also asked about a message he sent on Oct. 14, 2008 to an American woman he met online that he "crossed the line on Friday" and "liked it."

Twitchell told the jury that he was referring to an encounter with an ex-girlfriend.

Twitchell also admitted he is the author of the 42-page document known as "SKconfessions" which police retrieved from the hard drive of his laptop computer.

The document outlines the luring, killing and dismembering of a man the author lures to a garage by posing as a woman on an internet dating site.

The Crown alleges the document is Twitchell's personal diary. Twitchell told the jury that the thoughts and editorial comments in the document were fictional.

Twitchell's testimony is expected to continue on Thursday.

With files from the CBC's Briar Stewart and Janice Johnston