The former owner ran a funeral home, now closed, that contracted with Magee-Women's Hospital in Pittsburgh to cremate aborted or miscarried foetuses. The funeral home director, Robert Winston, is cooperating with police and is not charged with any offence, according to his lawyer, James Ecker. Officials declined to speculate why Winston kept the foetuses rather than dispose of them.

Most of the foetuses were less than 16 weeks old, the point below which a foetus is treated as a "surgical specimen" and is not legally required to be reported to the police or coroner, said Dr Cyril Wecht, coroner for Allegheny County.

At 16 weeks or more, a foetus is considered a body and subject to autopsy to determine the cause of death, he said. The foetuses date from 1999 to 2002.

"We can appreciate the emotional trauma these families have suffered and we want to be able to say accurately and honestly what we have," Mr Wecht said.

The identification process should be complete by next week, he said. In some cases, Mr Wecht said some families may choose to bury the foetuses.

A foetus in the womb - Enlarged photo