Washington - An adoptive mother in Maryland was arrested for child abuse in a case that involved the killing, then freezing the remains of two of her children, media reports said Wednesday.

The mother, Renee Bowman, 43, has been charged with child abuse after a man in her rural Calvert County neighbourhood stopped to help a third adopted child, age 7, whom he found wandering in her nightgown and caked in mud.

After police were contacted, investigators found the bodies believed to be those of two of Bowman's other adopted children encased in ice in a freezer in her home, the Washington Post reported.

The two other children, who have now been reported officially missing, would be 9 and 11.

Police suspected that the children were killed more than a year ago and put into the freezer. As Bowman moved around in the Washington capital region, she appeared to have moved the freezer with her, reports said.

No formal charges of murder have been filed, according to the reports.