PORTLAND, Ore. (KOIN) — A 35-year-old man plead not guilty Tuesday to charges related to the methadone overdose and death of his 2-year-old nephew.

Willie Lee Harris Jr.’s nephew, Reginald Harris Jr., died of a lethal dose of methadone on October 10, officials tell KOIN 6 News.

Willie Lee Harris Jr. in his first court appearance in Portland, October 18, 2016 (KOIN)

Harris’ mother, Pamela Harris, said by phone Tuesday she does not believe her son would have done anything intentionally to cause the child’s death. She said Reginald got a hold of the methadone while riding in Harris’ car, consumed it, became ill and died.

Police do not believe Harris gave his nephew methadone, rather it was left in a place where he had access to it.

Harris was arrested shortly before 1 a.m. Tuesday in the area of NW 16th Avenue and Flanders Street and was booked into Multnomah County Detention Center.

He is charged with second-degree manslaughter, criminally negligent homicide, first-degree criminal mistreatment and unlawful possession of heroin.

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“This case is a tragic reminder to keep all prescription drugs in a safe place where children do not have access to them,” Sgt. Pete Simpson said in a statement.

According to records, Harris has a separate pending case in Washington County that has gone into warrant status. He was indicted in Feb. 2015 for charges of possession of heroin, possession of cocaine, DUII, giving false information to police and failing to carry a driver’s license. A trial date has not been set.

Harris’ bail has been set at $325,000.

Records show Harris was convicted of delivery and manufacture of a controlled substance and giving false information to police in 2001. He also has a conviction out of Louisiana for felony possession of heroin.

The Multnomah County Child Abuse Team and Portland Police Bureau’s Homicide Detail are investigating the case.