A blood spatter expert told the jury in the Mark Twitchell murder trial that he found blood in cars belonging to the accused and his alleged victim, Johnny Altinger.

Edmonton Police Const. Fons Chafe testified Monday he found blood transfer stains in Twitchell's Pontiac Grand Am and the Mazda 3 belonging to Altinger.

He also found streaks of blood on the bumper of Altinger's car that were visible to the naked eye.

Chafe told the jury that stains were found inside and outside the garage where Altinger was allegedly attacked — more than 266 on the garage door alone.

He used the stains to determine that they came from four "impact points of origin" within the garage, presented in a diagram that was shown to the jury.

Under cross-examination by Twitchell's lawyer, Charles Davison, Chafe conceded that he had not tested all the stains to make sure they were blood.

The jury has been told Twitchell made a movie inside that same garage and used a mixture of water, corn syrup and red food colouring as a stand-in for blood.

"The reliability and integrity of the diagram ... depends on each of those stains being blood," Davison said.

Davison asked Chafe if the syrup mixture could be mistaken for blood. Chafe said he was confident the stains he saw in the garage had the consistency, colour and appearance of blood.

Last week, an RCMP DNA expert testified Altinger's blood was found on a number of items seized from Twitchell's home and car, and his parents' home, including a pair of jeans.

Twitchell, 31, is accused of killing Altinger, 38, on Oct. 10, 2008. The Crown believes Twitchell, an aspiring filmmaker, lured Altinger to a rented garage in south Edmonton by posing as a woman on an online dating site.

Twitchell's first-degree murder trial is in its fourth week in Edmonton Court of Queen's Bench.

With files from the CBC's Janice Johnston and Terry Reith