Beverly Rowbotham spent more money than usual on a grocery trip the day she died, a jury heard Wednesday at her husband's murder trial.

Beverly Rowbotham was found dead in her car at a gas station near Selkirk, Man. (CBC)

Hours before she was found dead in her car, Rowbotham spent $108.32 at the Safeway store in Selkirk, $33 more than the average spent in her previous visits, said Linda Fortne, the store's assistant manager at the time.

The dollar figure could be key in the second-degree murder trial of Rowbotham's husband, Mark Stobbe, a high-level political adviser in Saskatchewan and Manitoba.

Crown witnesses have said Stobbe told them his wife disappeared while out for groceries the night of Oct. 24, 2000. They said Stobbe told them Rowbotham had been at Safeway earlier in the day, but had to leave because her youngest son was acting up, so she planned to return later that evening.

The Crown is trying to poke holes in that story.

Rowbotham's $108.32 in purchases was more than usual, according to store records produced by Fortne. Store surveillance cameras show Rowbotham spent 46 minutes in the store and she appeared to be in no rush. "She spent quite a bit of time in the meat department," Fortne said.

Mark Stobbe is charged with second-degree murder in the death of his wife, Beverly Rowbotham. (CBC)

While Rowbotham was not caught continuously on camera, the images that were captured do not show her son acting up.

The Crown's theory is that Stobbe killed his wife in the couple's sprawling rural backyard in St. Andrew's, Man., by hitting her in the head with a hatchet 16 times. The Crown alleges Stobbe then drove his wife's body to a parking lot in Selkirk, 15 kilometres away, before riding a bicycle back home and reporting her missing.

Physical evidence produced so far includes small bone fragments, drops of blood and other material found in the backyard. DNA testing showed the remnants came from Rowbotham.

Stobbe had been a senior adviser to Saskatchewan Premier RoyRomanow, and moved to Manitoba in 2000 to take a senior communications job with the NDP government that had been elected the previous year.