LAWRENCE (CBS) – The man charged in the tragic death of his 11-year-old niece last year was ordered held without bail Tuesday, after it is was revealed the girl was exposed to fentanyl.  Miguel Rivera, 58, of Lawrence was arrested Friday night in connection with the death of Precious Wallaces.

Miguel Rivera in Lawrence District Court, Jan. 22, 2019. (WBZ-TV)

Wallaces, a sixth grader from Haverhill, was staying at Rivera’s apartment on Jackson Street in Lawrence December 15 with her brother when she started to struggle to breathe in the middle of the night. She was rushed to the hospital and passed away days later.

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Precious Wallaces. (Family photo)

Court documents released Tuesday revealed that Precious tested positive for fentanyl in her system.

Rivera was interviewed multiple times by investigators and, according to the documents, ultimately admitted that he left his apartment to throw away sleeping pills while his niece was in distress.  He said he feared that she had taken some in his bathroom.

He’s now charged with lying to police and permitting substantial bodily injury to a child. A not guilty plea was entered on his behalf at his arraignment in Lawrence District Court Tuesday.

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The Essex District Attorney’s Office said it’s possible that more charges could be filed in the case.

Rivera is due back in court January 29.