A dog trained to sniff out decomposed bodies gave an alert at Hadden Clark's family burial plot on Cape Cod, where Montgomery County prosecutors say Clark buried little Michele Dorr before moving her body and hiding it again six years later.

Kathleen Barrett, a Massachusetts state trooper, testified at Clark's trial yesterday that her German shepherd searched the cemetery in January 1993 and pawed at soil removed from a hole that prosecutors say was just large enough to bury a small child.

Clark is on trial in the slaying of 6-year-old Michele, who vanished from the back yard of her father's Silver Spring home in May 1986.

The girl's body has never been found, but prosecutors have told the jury that they believe Clark buried her in his family's cemetery plot in Wellfleet, Mass., then dug up the body and moved it on Halloween night in 1992.

Clark was a suspect at the time in the disappearance of Laura Houghteling, 23, from her Bethesda home, but the jury won't be told that. Montgomery Circuit Court Judge Michael D. Mason ruled earlier this week that the jury may not hear anything related to Clark's having pleaded guilty to killing Houghteling, a crime for which he is now serving 30 years.

It was after Montgomery police interrogated Clark about Houghteling's whereabouts in October 1992, but before he was arrested in her slaying, that prosecutors say Clark drove to Massachusetts to exhume Michele's body.

Police sent cadaver-detecting dogs into the Clark family cemetery plot in January 1993 during the search for Houghteling's body. Barrett testified that her dog, Dan, smelled human remains at a small patch of sandy soil near one of three headstones in the plot where Clark's father and paternal grandparents are buried.

Police found no body or bones there, she said, but the dog showed intense interest in soil removed from the hole.

Defense lawyer Brian Shefferman questioned whether the German shepherd's nose could be trusted, telling the jury that the dog had made mistakes during training, such as alerting to deer bones and a bear paw during his training classes.

Noting that the dog was sniffing in an old cemetery, Shefferman pointed out that the scent of human remains, particularly in unembalmed bodies, can remain in the earth for up to 100 years and can carry through the ground via underground water.

Prosecutors also called on Clark's sister, Alison Huggins, to testify yesterday about her brother showing up unannounced at her Rhode Island home on Halloween night in 1992 appearing "disheveled" and "very nervous."

"He said to me that the police were trying to pin a crime on him because he was a homeless man," Huggins said.

When she invited her brother to stay with her or accept money for a hotel room, Huggins said, "he said he had to keep on moving."

Prosecutors have told the jury that a Massachusetts woman will testify that she saw Clark's white truck pull into his family's burial grounds on Halloween night.

In 1993, Clark plead guilty to murdering Houghteling and then led police to her body buried off Old Georgetown Road.