TORONTO -- A Toronto-area father and stepmother who fatally abused the man's 10-year-old son have lost a bid to have their convictions overturned.

Garfield Boothe and Nichelle Rowe-Boothe were found guilty two years ago of second-degree murder in the death of Shakeil Boothe, whose frail and beaten body was found in his bed in Brampton, Ont., in 2011.

Both received an automatic life sentence, with Rowe-Boothe ineligible for parole for 13 years and her husband for 18 years.

In filing her appeal, Rowe-Boothe argued the trial judge had erred in finding that her statements to police before her arrest were voluntary.

Garfield Boothe, meanwhile, listed among the grounds of appeal that Ontario Superior Court Justice Fletcher Dawson refused to try him and his wife separately.

But a three-judge panel with the Court of Appeal for Ontario dismissed the couple's arguments, saying Dawson had made no errors.

Boothe had argued that Dawson's refusal to grant him a separate trial resulted in an injustice, but the panel said he "failed to establish" that was the case.

The judges also found Rowe-Boothe, who had said police should have warned her she could be incriminating herself, had failed to prove any mistake on Dawson's end.

"First, the trial judge reasonably decided, based on an objective view of all of the circumstances, that her statements during the telephone interview were voluntary," they said in a written decision.

"Second, the trial judge did not fail to consider adequately the impact on Ms. Rowe-Boothe of the police officer's assertion that Ms. Rowe-Boothe's lawyer would be unavailable for the remainder of the interview at the police station. His decisions are fully supported by the evidence and no reason has been demonstrated for interference by this court."

During trial, the couple blamed each other for Shakeil's death, but the trial judge ruled Shakeil's father delivered the brutal beating that pushed the sickly boy over the edge.

While both Boothe and Rowe-Boothe betrayed Shakeil and contributed to his death, the father played a larger role and admitted he regularly hit his son, Dawson said at the time. Shakeil was also chained to his bed.

The boy's stepmother was nonetheless "a partner in the abuse and neglect of Shakeil" even though there was no evidence she struck him, save for one incident in the fall of 2010, he said.

Both have been in custody since their arrest in May 2011 and that time will count toward their sentences.

Shakeil came from Jamaica to live with his father in Brampton in 2009. He was found dead in his bed on May 27, 2011, but evidence heard at trial suggests he died a day earlier.

The pathologist who examined Shakeil's body found that while his death was triggered by a severe beating, the boy was already in a downward spiral due to malnutrition and a severe infection that saw pus forming in his lungs.