Erika Mendieta, 34, was found guilty of manslaughter by a Toronto judge in the beating death of her toddler, who died in 2003.

An Ontario Superior Court justice has found a Toronto mother guilty of manslaughter in the 2003 beating death of her two-year-old daughter, ending a trial plagued by controversy.

In her ruling, Judge Nola Garton said she believed Erika Mendieta, 34, struck her daughter, Emmily Lucas, a number of times on Nov. 13, 2003, out of frustration.

Mendieta had pleaded not guilty to second-degree murder.

Garton also said she didn't believe that Mendieta's former live-in boyfriend, Johnny Bermudez, caused the toddler's death. Bermudez had testified that he killed Emmily. He cannot be prosecuted because he is protected by the Canada Evidence Act.

Mendieta's daughter was beaten to the point of convulsions and had bruises all over her body. She was taken to Toronto's Hospital for Sick Children where she died 10 days later.

Reacting to the ruling, the child's father Derrick Parra said, "My daughter can rest in peace now finally."

Last November, some members of the Toronto jury complained a man distracted them by sitting in the front row and making "strange faces," while Mendieta was on the stand.

The man turned out to be Crown attorney Paul Alexander, who helped prosecute Mendieta during her first trial, which ended in a hung jury. He wasn't involved in her retrial.

Garton then declared a mistrial and dismissed the jury before giving her consent to move ahead with a third trial after both sides agreed to a judge-only trial.

Mendieta will be sentenced Feb. 11.