LINDEN — Searchers have found about 1,000 bone fragments in an abandoned well as they pursue information provided by a serial killer who is claiming to disclose the location of long-lost victims, authorities said Wednesday.

Investigators intend to make a decision about exploring a second nearby well after wrapping up the excavation of the first site near the farming town of Linden, about 12 miles outside of Stockton, San Joaquin Sheriff's Department spokesman Les Garcia said.

More than 50 calls have been made to a hotline set up by authorities for people who believe their loved ones might be among the victims of Wesley Shermantine and Loren Herzog.

Officials already have positively identified the remains of two female victims buried on Calaveras County property once owned by Shermantine's family.

Shermantine and Herzog were dubbed the "Speed Freak Killers" after their 1999 arrest. Investigators said the boyhood friends were suspected in as many as 20 murders.

Shermantine has said many more remains could be found at the well, where digging resumed Wednesday after being hampered by rain.

Shermantine is on Death Row after he was convicted in 2001 of four murders. He is making the disclosures after Sacramento bounty hunter Leonard Padilla promised to pay him $33,000. Herzog hanged himself last month after learning Shermantine was disclosing the victims' locations.