HOUSTON – Authorities have dug up human skeletal remains in a field where they've been searching for a teenage girl who went missing for nearly 20 years.

The medical examiner's office is investigating whether the remains belong to Jessica Cain, who went missing from Texas City in 1997.

"If it's not Jessica Cain, then we have to find out who it is," said Houston Homicide Detective Richard Martinez. "There's enough there to know that it's a body, so they still have to keep digging and meticulously get every bone they can.

The remains were found around 2:30 Friday afternoon when a backhoe operator found what he thought were skeletal remains, according to detectives. Those suspicions were confirmed after an anthropologist conducted an investigation.

Martinez said the remains were found about four feet in the ground to find the remains.

"We don't know what the conditions of the field were back in 1997," he said.

Crews have been digging in the field for more than three weeks after convict William Reece tipped them off that Cain's remains could be found in the field. Reece, who's serving time for aggravated kidnapping, has been linked to at least five murders or kidnappings—all from 1997.

The Houston Police Department is the lead agency in the investigation. Investigators said they'll work in conjunction with other departments, such as the Friendswood Police Department, if, in fact, they are Cain's remains.