A Manitoba man has been acquitted of repeatedly sexually assaulting his young stepdaughter after a judge said she could not rule out suggestions the girl's mother had coached her to lie.

"In all, I simply can't be sure as to what was going on with this family," Justice Karen Simonsen said in a 21-page written ruling delivered Tuesday.

"When I consider the evidence as a whole, I am left with uncertainty as to whether the accused committed the alleged acts and I have a real doubt as to whether the complainant was reporting the allegations at the behest of, or under the persuasive influence of her mother," Simonsen said.

The man stood trial accused of assaulting the girl on repeated occasions between 2009 and 2011, beginning when the girl was two years old.

At trial, court heard testimony the girl disclosed the allegations to her mother in March 2011. In a subsequent police interview, the girl alleged her stepfather had engaged her in acts of oral and anal sex.

The girl's mother and a co-worker of the accused both testified the accused confessed to assaulting the girl.

Court also heard testimony the accused and the girl's mother had sex on at least two occasions after the allegations came to light, at a time when the two were to have no contact with each other.

"Despite her (the mother) explaining her belief that marriage is forever, this is difficult to understand," Simonsen said.

The accused denied confessing to the allegations and argued the girl's mother had coerced her daughter into lying about the assaults so she could end her relationship with him. The man alleged the woman had previously threatened to move away with their children if he couldn't come up with the money to provide for them.

During a police video statement, the girl described certain allegations only after taking a bathroom break with her mother, Simonsen said.

"Although the officer who took the statement testified that he heard no conversation between them while in the bathroom, his evidence is not an answer to the real risk that the mother took the opportunity to pressure or coach the complainant," Simonsen said.

Under cross-examination the girl admitted her mother had spoken to her "15 or 20 times" about what to say in court and that the two of them "had secrets."

"Although she was never challenged as to whether the accused committed the alleged conduct or whether she was lying about it, her testimony nonetheless raises concerns as to the extent of involvement of the mother," Simonsen said.

dean.pritchard@sunmedia.ca

Twitter: @deanatwpgsun