MUSKOGEE COUNTY, Oklahoma - A Muskogee County grandmother accused of giving her 3-year-old grandson a fatal dose of morphine is facing a second-degree murder charge.

Muskogee County District Attorney, Orvil Loge, said police arrested Kimberly Morning Friday after the medical examiner’s report listed homicide as the cause of death.

"Whenever the medical examiner did the toxicology, it came back that he had three-time the adult limit of morphine in his system. And at that point we knew it wasn't an accident, that someone had intentionally given him some morphine," he said.

Loge charged the child's grandmother with second-degree murder after he got the ME’s report.

"We allege that she crushed an extended release morphine tablet, put it into his sippy cup, which he consumed, which caused his death," he said.

Court documents show Morning, who was babysitting, admitted she crushed the morphine tablet and had intentionally put it in the child's sippy cup to calm him down because she was frustrated and running out of patience with him.

Loge said, "Normally you have cases where parents or relative will give, maybe Motrin, or Benadryl or something over the counter, but never morphine or a narcotic as powerful as morphine."

Family members told police that before the child was put down for a nap he had a headache and diarrhea.

The medical examiner said, in addition to the morphine, the child was regularly given other medication to control his hyperactivity, but the medical examiner only listed morphine as the cause of death.

If convicted, Morning could face life in prison. She's expected back in court December 7th. Her bond is $100,000.

We stopped by the suspect’s house, but the family didn't want to talk.