Mark Twitchell is accused of killing a total stranger, then trying to concoct an airtight alibi to match the perfect murder in one of his movie scripts.

But within minutes of meeting Twitchell, police had a hardware store receipt that suggested the fringe filmmaker was lying through his teeth, court heard Wednesday.

Twitchell, 32, is charged with first-degree murder in the death of 38-year-old Johnny Altinger on Oct. 10, 2008.

Prosecutors say they'll prove Twitchell posed as a woman on an Internet dating website to lure Altinger to a garage on Edmonton's south side. Once his victim arrived, Twitched knifed him to death, cut up and burned the body, then dumped the remains in a sewer.

They say the death mimicked a seven-minute slasher movie Twitchell had just shot and that the killing was part of his grander plan to become a serial killer.

Const. Christopher Maxwell testified Wednesday that he was the first officer to talk to Twitchell. Police had been called by Altinger's friends. They hadn't seen him in a week and figured the emails they were getting from him saying he'd run off with a woman to Costa Rica were bogus.

Police had tracked Altinger's last known location to the garage rented by Twitchell.

Twitchell denied all, said Maxwell. "They were very brief, short responses," he said.

Twitchell said he hadn't been in the garage for a week and didn't know Altinger.

But police still needed to see inside the garage, so late on a Saturday night, eight days after Altinger's disappearance, Twitchell met up with Maxwell and Sgt. Colleen Maynes.

He opened the garage's back door. There, under a naked yellow bulb, was a yawning empty space save for a chair, a couple of tables, a steel barrel of burned remains and sundry soiled bric-a brac.

There was a strong whiff of gasoline. Twitchell said he didn't know how remains got in the barrel.

On a table were cleaning supplies -- ammonia and paper towels -- and a receipt for them.

It was dated Oct. 15. Maynes recalled that Twitchell had said he hadn't been at the garage since the 10th.

There was a credit card number at the bottom of the receipt. Maynes dialled her cellphone to call Maxwell, who by this time was outside the garage sitting in a patrol car with Twitchell.

Ask Twitchell what the numbers are on his credit card, she instructed.

Maxwell did. Twitchell flipped through his wallet. The numbers matched.

From there, court has heard, the investigation into the missing Altinger became a murder probe. And Twitchell's world rapidly became unglued.

Court has heard Twitchell was a filmmaker trying to bust into the biz fulltime. He had made a low-budget "Star Wars" tribute movie on green screens at a local college a few years earlier but was otherwise going nowhere.

He had a wife, a young daughter, a house in the suburbs and an unsatisfying string of dead-end sales jobs.

He was fascinated by Dexter Morgan, a fictional character in TV and books who works as a police forensic analyst by day but kills strangers in the name of vigilante justice by night.

Prosecutors allege that in the summer of 2008 Twitchell began scheming a new Dexter-type double life. He bought knives, saws, tape, a hockey mask, a stun baton and handcuffs.

He rented the garage and over one weekend he and some friends filmed a short movie about a married man lured to a remote location for an Internet date with another woman.

The movie victim is strapped to a metal chair inside an enclosed space and threatened with death for his computer pass codes by a man in a hockey mask. He is then killed and dismembered.

Altinger was not married, but prosecutors say he died in a similar fashion two weeks after the movie was shot.

Altinger's friends have testified that in the days after his disappearance, someone using his email sent them notes saying he'd quit his job and run off with a woman named Jen.

That didn't sound like Johnny, they said. The Johnny they knew was not impulsive. He was a planner, hated tropical locales and always ended his emails with a joke. They went to his home and found his beach gear and passport.

The Crown has already entered into evidence blood-stained knives, saws and a cleaver found in Twitchell's possession.

Police later found Altinger's car a few blocks from the garage at a friend of Twitchell's. Prosecutors say Twitchell eventually told detectives he bought the car off a stranger for $40.

Altinger's blood was found in the garage and in the trunk of Twitchell's car.

At the start of his trial, Twitchell tried to plead guilty to interfering with Altinger's corpse -- but not murder. His plea was rejected.