PAWNEE COUNTY, Oklahoma - A rural Pawnee County field could be the key to unlocking a 21-year-old cold case. The OSBI says a recent tip led agents to a field near Terlton, where investigators have been digging for three days.

It's been nearly 21 years since anyone has seen or heard from Wendy Camp, her 6-year-old daughter, Cynthia Britto, and Camp's friend, Lisa Kregear. The three had gone to visit Camp's son in Shamrock.

Camp had multiple sclerosis, so her ex-mother-in-law, Beverly Noe, was driving them back home to Oklahoma City. Noe told investigators she got into a fight with Camp and left all three at the Chandler Walmart.

That was the last anyone ever saw of the two women and the little girl.

Camp's mother, Jackie Taylor, was outspoken in a 2006 interview, saying she's certain Noe played a role in the disappearance.

"I absolutely know without a shadow of a doubt in my in my heart they were all murdered that night," Taylor said.

At the time, police said the three seemed to have vanished without a trace. Foul play was always suspected, but no arrests were ever made and the case eventually went cold.

But on Monday, the OSBI started digging in the field near Terlton. And Wednesday, tents were up, shielding the dig.

But from the sky, you can see a hole about four feet deep and investigators sifting through possible evidence.

"We are in an area looking for anything that might pertain to the three missing people in this case, any artifacts, anything that we can find that could put them in that location, at least at some point in time," said OSBI spokesperson Jessica Brown.

Brown said investigators have received many tips on the case over the years, and have even performed similar digs.

"We are hopeful, but it's just another lead we are running on right now," Brown said.

Neighbors say the current property owners didn't live on the land at the time of the disappearance.

Brown said she can't confirm that anything has been found and said the OSBI will be on the site for at least the rest of the week.