DETROIT -- The Wayne County Medical Examiner's office continues to investigate the discovery of the charred remains of a baby boy, whose parents are facing child abuse charges.

Joseph Miller and Nikki Reid, of Lillibridge Street, are accused of burning their 1-year-old son while giving him a bath. But they are also under investigation in the death of one of their other children – a baby who relatives say had been missing for several months.

According to police, the remains of the baby were hidden in the ceiling of Miller's sister's basement on Lappin Street, about 5.5 miles away from his house, without her knowledge. Police reports also say that Miller had tried to burn the baby's remains on a barbecue grill.

Miller and Reid lived with their five sons, all younger than the age of 5. But for the last several months, relatives had been wondering about the whereabouts of one of their children. They were told he was with other relatives, but Miller's sister had doubts.

The sister, Tammy Johnson, said that she told relatives, "I'm getting the feeling that the baby is not alive."

Johnson said her brother recently stopped by to do laundry at her house. As part of investigation, police went to her home and found the body. It is unclear how long the body was there. An anthropologist is studying the remains to determine if the baby died from natural causes.

As police continue to investigate before a decision is made on whether to charge the couple in the death, the Michigan Attorney General's office is asking the courts to terminate the parental rights for Reid and Miller for their remaining four children who are in protective custody.

Reid is jailed under a $400,000 bond. Miller's bond is $700,000.