Letts-Beckett drowned in Upper Arrow Lake on August 18, 2010. Her death was initially believed to have been accidental, but Beckett was charged with murder one year later.
The Crown has alleged Letts-Beckett was killed out of greed, saying Beckett's motive was financial. Prosecutor Sarah Firestone has told jurors Beckett stood to gain a significant amount of money in life insurance and accidental-death benefits, as well as Letts-Beckett's schoolteacher pension.
Turko tried to poke holes in the Crown's case against Beckett, saying most prosecution witnesses "actually support the evidence of Mr Beckett".
She also offered a number of points for jurors to consider: The marriage between Beckett and Letts-Beckett was not strained; Letts-Beckett's relationship with her family was strained; Letts-Beckett suffered from depression, could have been suicidal and was self-medicating; Letts-Beckett obtained life insurance policies without Beckett's knowledge; and a jailhouse snitch called by the Crown, who can only be identified as Agent A, is unreliable.
"[Agent A] is a rat who likes to lie and likes to lie for money," Turko said.
Agent A, Beckett's former cellmate, testified over a period of days, telling jurors he had been essentially hired by Beckett to kill Crown witnesses upon his release from jail.
Beckett took the stand briefly in his own defence following Turko's opening.
Her first question for her client was a straight-forward one: "Did you push your wife off the boat or drown her?"
"No, I did not," Beckett replied.
Beckett then proceeded to give a rambling history of how he met Letts-Beckett, rife with tangential explainers and New Zealand trivia.
Among them, Beckett explained to jurors the origin of the term "Kiwi" as it relates to New Zealanders - "Kiwis aren't named because of the kiwifruit, they're named because of the kiwi bird, which is flightless," he said - the origin of the name Cape Kidnappers, the life cycle of gannets and hot fishing spots for marlin and tuna on New Zealand's North Island.
Beckett's testimony is expected to resume later this week. In the meantime, Turko said she will call friends, family and experts to give defence evidence.
Beckett and Letts-Beckett met in 1995 in New Zealand. Five years later, he moved to Westlock, Alberta, to be closer to her. The couple married in 2003.
Previous witnesses have described their relationship as a rocky one. The Becketts split briefly in late 2007 but reconciled months later.
Through her questioning, defence lawyer Donna Turko has suggested Letts-Beckett was depressed prior to her drowning.
His trial, which began in mid-January, had been expected to last three months.