TULSA, Oklahoma - There’s been a major breakthrough in a homicide investigation that started more than 15 years ago.

Tulsa Police say the hunt for two killers is over.

Joe Calvert and Shanna Ramsey are behind bars in New Mexico charged with the murder of Latricia Fipps. 

She was last seen leaving her job with ex-boyfriend Joe Calvert.

He claims he dropped her off at home, but police say that's not what happened.

Tulsa County prosecutors charged Joe Calvert and Shanna Ramsey with the murder of Tricia Fipps. 

Investigators said in November 2002 they kidnapped her, killed her, and left her body in New Mexico. 

"We think Calvert is the one who killed Fipps and Ramsey was complicit in hiding the body and they lived their life in New Mexico ever since," said Sergeant Dave Walker. 

For 16 years detectives from Oklahoma and New Mexico have been keeping an eye on the pair, working with witnesses to build a case without Fipps remains. 

"Even though we knew where they were they didn't know we were looking at them that hard," Walker said. 

It all came to an end Friday when the couple was pulled over in New Mexico. 

"They were oblivious to the fact they were going to get arrested and so I think the arrest went without a hitch," Walker said.  

The news is a relief for Tricia's mom, Sheila Owen, who told News On 6’s Lori Fullbright in 2014 how hard this has been for her family. 

"It's bad enough when somebody gets killed with a violent crime, you know, but not to have your child, you know, is the hardest part not knowing where she is," Owen said. 

Police admit they still don't know where Tricia's remains are, but at least now they believe they caught those responsible for her death. 

“I want him to go to prison for the rest of his life so he has to think every day about why he was there cuz the only crime she ever committed was being in love with that man," said Owen. 

The only thing they still want is to find out where Tricia was buried so they can bring her home.