French police began digging for clues Tuesday outside a former home of a confessed serial killer (search) who claimed last week to have murdered nine people and buried several of the bodies, a prosecutor said.

Michel Fourniret's (search) former neighbors in Clairefontaine, west of Paris, called police to say they remembered him behaving suspiciously, prosecutor Yves Charpenel said in a telephone interview. Fourniret was seen in the yard burying objects and possibly clothing, LCI television reported. But officials said they discovered nothing unusual, just an unused septic tank.

Fourniret's neighbors in Clairefontaine (search) contacted police after a call for witnesses was issued over the weekend.

"We're going to be getting more of these," Charpenel said. "All the neighbors who lived around the numerous homes of the Fournirets over the last 30 years potentially have revelations to make."

Officials believe Fourniret and his estranged wife Monique Olivier lived in the two-story stone house in Clairefontaine at the end of the 1980s, though the exact dates were not clear.

On Saturday, Fourniret, 62, led police to two bodies buried in the woods near another former home, an 18th century chateau in northern France.

Forensic specialists were performing autopsies on what they believe are the remains of Jeanne-Marie Desramault, 22, and Elisabeth Brichet, 12. Both were reported missing in 1989. Results were expected Wednesday, the prosecutor said.

Charpenel said investigators were unsure what they would find in the new search because they were not acting on Fourniret's own testimony.

Fourniret has been jailed in Belgium for (search) about a year, but the case took a major turn last month after his estranged wife accused him of a string of killings beginning in 1987. French officials are investigating whether she took part in the crimes.

Officials said they would reopen about 30 unsolved investigations after Fourniret's alleged confession. Investigators say he took responsibility for nine killings between 1987 to 2001 — seven girls or young women, as well as two adults where the motive was believed to be robbery.