The woman accused of running a puppy mill in Groton is being held on a high bond at the Niantic women's prison because she won't reveal her identity.

She is listed as 59-year-old Linda Snow or Mary Howard on official documents, but a police investigation has revealed that both of those are assumed identities, according to detective Lt. John W. Varone of the Groton Town Police Department. The real Linda Snow was a Massachusetts woman who died years ago.

Varone said detectives have learned that the woman may be from Canada.

"We are actively pursuing it, and we have leads that are taking us north of the border," Varone said.

Police charged the woman last month with five counts of cruelty to animals, in addition to criminal impersonation and interfering with a police officer, after they discovered five dogs with matted fur and amid animal waste, without food and water at her house at 59 Oslo St. in Mystic.

The woman initially identified herself as Mary Howard, but police learned that the same person had been charged in a Massachusetts animal cruelty case under the name Linda Snow.

That name, too, turned out to be false.

When the police notified the court that the woman was neither Mary Howard nor Linda Snow, she was asked in open court to identify herself.

"She wouldn't disclose on the record what her true identity is," said her attorney, public defender Jennifer B. Nowak.

A judge raised her bond from $50,000 to $250,000, and she has remained in custody at the Janet S. York Correctional Institution since Feb. 18.

The mystery of her identity was not resolved when she made another court appearance on Wednesday, and the case was continued to March 28.

"I'm not going to comment," Nowak said when asked if she knows the true identity of her client.

The case has puzzled officials since police went to a home on Oslo Street last month home to contact a Mary Howard who had brought a man she said was her husband, Michael Howard, to the Old Mystic Fire Department on Jan. 1 for a medical emergency. Officials from Lawrence & Memorial Hospital told police the woman never returned to visit the man, who was in a vegetative state. The hospital said they hadn't been able to contact her, and couldn't find information or a Social Security number for Michael Howard.

Police tried to find Mary Howard at the address she had given, 35 Oslo St., but it didn't exist. However, they found a van registered to Mary Howard of 1375 Chapel St., New Haven, in the driveway of 59 Oslo St. Police told Howard she had to go to the hospital to make arrangements for her husband, but later learned she had never gone.

Through fingerprints, the FBI identified the "husband" as Mark J. Zimmerman, who has a criminal history in Florida, Texas and Massachusetts. They learned that during Zimmerman's arrest in Massachusetts, a co-defendant was a woman named Linda Snow. Working with police in Stoughton, Mass., through photographs, Groton detectives determined that Mary Howard and Linda Snow were the same person.

On Feb. 17, the police executed a search-and-seizure warrant at 59 Oslo St. and found the dogs. Their owner was taken into custody, and eventually identified herself as Linda Snow. The identity was confirmed through fingerprints, but police learned later that the real Linda Snow had died years ago and that the woman in the dog case had assumed her identity.

The "husband," who was actually a boyfriend, is now recovering in a rehabilitation facility.

k.florin@theday.com