Investigators working on the case of a mother who allegedly hid several tiny bodies around her home have a daunting task ahead of them, both forensic and legal.

Even as FBI and local searchers prepared Wednesday to finish a three-day search of 37-year-old Christy Freeman's home, the four sets of pre-term remains already recovered pose dilemmas.

Investigators must first determine whether all four bodies were the offspring of Freeman, who has four living children. She has been charged in the death of one of the pre-term infants, a 26-week-old fetus discovered under her bathroom sink last week.

Then investigators need to find out how old the other pre-term infants were when they died, when they died — and whether Freeman or someone else was responsible for their dying before birth.

The timing in Freeman's case is critical. If the pre-term infants were too young to be considered viable outside the womb, Freeman can't be charged with murder. And if they were old enough to live outside the womb, but died before Maryland passed its 2005 fetal homicide law, it may not be a crime even if Freeman caused their deaths.

The law, designed to penalize those who kill a pregnant woman or her viable fetus, includes a provision shielding pregnant women from prosecution for actions that result in their own fetus's death.

The exemption, meant to preserve the right to an abortion, hasn't been challenged in the courts, said Denise Burke, vice president and legal director of Americans United for Life, a Chicago-based group that seeks common ground on abortion issues.

Cindy Boersma, legislative director of the American Civil Liberties Union of Maryland, said there is nothing ambiguous about the exemption.

"The only reason the bill passed was because it explicitly contained that exemption," she said.

State Delegate Susan K. McComas, a Republican who co-sponsored the 2005 bill, said the exemption was added by majority Democrats who feared the bill would restrict a woman's right to abortion. "We weren't contemplating a woman doing something to her own fetus," McComas said.

Prosecutors and police concede it could take months to sort out all the physical evidence and determine what charges, if any, may be appropriate for Freeman if the three sets of older remains found in her home and Winnebago belonged to her.

"It may turn into a war of experts, with the prosecution experts saying the fetus was viable and the defense experts saying the fetus was not viable, or it's impossible to know whether the fetus was viable," said Baltimore attorney Andrew D. Levy.

Ocean City Police Chief Bernadette DiPino cited the delicate investigation ahead Tuesday when she explained to reporters why searchers went through dirt from a vacant lot next to Freeman's home shovel by shovel.

"We need to gather as much evidence as we can," she said. Talking about the prosecutor, State's Attorney Joel Todd, she added, "he's going to have a challenging case as it is."

Freeman longtime boyfriend, Raymond W. Godman Jr., has not been named as a suspect in the case and was staying with the couple's four children at a friend's house, said Ocean City Police Spokesman Barry Neeb.

DiPino also said that a specialist planned to examine Freeman to try to find out how she got bruises on her thighs, abdomen and forearm before she was admitted to a hospital Thursday with heavy bleeding.

Police want to know whether the bruises were accidental, self-inflicted or caused by someone else. They have not ruled out the possibility of charging someone else if they have reason to suspect someone caused Freeman's stillbirth.

Todd, the prosecutor, has said little about how he plans to proceed. He told reporters Monday that the state "will have to prove beyond a reasonable doubt that she did something to cause that baby to be stillborn."