HOUSTON — A convicted kidnapper who might be linked to other violent crimes has been helping investigators digging in a rural area of Houston look for the body of a teenager who disappeared nearly 20 years ago, his attorney said Friday.

William Reece, who is serving a 60-year sentence for a 1997 kidnapping, has been assisting authorities as they try to locate the body of Jessica Cain, said Reece's attorney, Anthony Osso.

The 17-year-old girl disappeared Aug. 17, 1997, after leaving a Bennigan's restaurant in suburban Houston following dinner with friends. Her tan Ford pickup was later found abandoned on Interstate 45, about five miles north of her home in the small village of Tiki Island near Galveston. At the time of her disappearance, investigators said there was no sign of a struggle and the truck was not ransacked. Cain's purse was found in the vehicle.

"I've met with him. I counseled him. He is continuing to cooperate with authorities," Osso said of the 56-year-old inmate.

Osso declined to comment on other details of the case or characterize whether Reece had confessed to a crime.

For more than a week now, authorities have been digging at a pasture in south Houston in the presence of Reece, who was temporarily released from prison to the custody of Galveston County officials.

On Friday, two excavators and a small bulldozer could be seen digging at the site. Osso said that Reece has been at the dig site working with investigators. At the site, flowers as well as red and yellow ribbons had been placed along a wire fence. A note had also been left that read in part, "Dearest Sweet 'Jessica,' You never leave my mind. #Justice for Jessica."

The FBI, the Texas Rangers, and police in the Houston suburbs of Friendswood and La Marque are involved with the investigation.

La Marque Police Chief Kirk Jackson declined to comment on what authorities were looking for at the dig site. Texas Department of Public Safety Sgt. William Kennard did not immediately return a call or email seeking comment.

Cain's parents could not be reached for comment Friday. Her father, C.H. Cain, previously told KTRK-TV in Houston that his family still held out hope his daughter was still alive.

"We're leaving it in God's hands," Cain told the station. "If God allows us to have our girl back, that'd be a big blessing."

Cain's disappearance is not the only missing person or abduction case that Reece is connected to.

In September, authorities in Oklahoma charged Reece with first degree-murder and kidnapping in the July 26, 1997, abduction and slaying of 19-year-old Tiffany Johnston. She was abducted from a car wash in Bethany, located northwest of Oklahoma City.

On Thursday, police in the North Texas city of Denton announced that Reece is a person of interest in the July 15, 1997, disappearance of 20-year-old Kelli Cox, a University of North Texas student who vanished after visiting a gas station.

"The Denton Police Department remains committed to actively searching for answers to Kelli's disappearance and will continue until the facts of her disappearance are known. Kelli's family remains in our thoughts and prayers," according to a police statement.

Reece had previously been named by police in Friendswood as the prime suspect in the April 3, 1997, abduction and murder of 12-year-old Laura Kate Smither.

Friendswood police spokeswoman Lisa Price declined to comment Friday on Smither's case, saying it was still an ongoing investigation. Reece has not been charged in the case.

Reece was convicted in 1998 for the May 16, 1997, Houston-area abduction of Sandra Sapaugh, who told authorities Reece forced her at knifepoint into his truck after first feigning to help her with a flat tire. Sapaugh was able to escape after jumping out of the truck as it went along Interstate 45.

Associated Press writer Nomaan Merchant in Dallas contributed to this report.

Follow Juan A. Lozano on Twitter at www.twitter.com/juanlozano70