NASHVILLE, Tenn. (WKRN) — Two East Nashville grandparents are facing first-degree murder charges following the fentanyl-related death of their 20-month-old grandson last year.

Charles Allen Sr., 80, and Yolanda Newsome, 58, were taken into custody Thursday at their S. 7th Street apartment.

Following an investigation, police say 20-month-old Korran Newsome was under the care of Allen and Newsome on August 6 while his mother was at work.

The grandparents placed Korran in bed with them that night, and after returning from work, Newsome told his mother that Korran was not breathing.

CPR was conducted on Korran at the scene. He was then rushed to Vanderbilt Children’s Hospital where he was pronounced dead.

Following a toxicology testing, the medical examiner ruled the cause of death to be acute fentanyl intoxication. Korran had enough fentanyl in his system to kill an adult, according to authorities.

After speaking with both of the grandparents, they acknowledged buying heroin off the street.

Police say they allowed Korran to become expeosed to heroin containing fentanyl while in their care, specifically in their bed.

Allen is being held on a $150,000 bond, while Newsome’s bond is set at $100,000.