TULSA, Oklahoma - Wednesday was the 20th anniversary of the murder of 16-year-old Dena Dean.

No arrest has ever been made, despite her parents' efforts to keep the case in the public eye.

For every year of the past 20 years, News On 6’s Lori Fullbright has been talking to Dena Dean's parents about her death and getting answers for her murder. 

They keep hoping every year that it's the last. This year, they are more hopeful than ever that's the case.

Dena Dean was a teenage girl who loved being in band and loved going to the car races with her family.
 
But, 20 years ago, friends say Dena decided to tell her boyfriend she was pregnant, even though she wasn't. Not long after, she went missing, then her body was recovered in a field days later.

Larry Dean, Dena's father: "I just want somebody held responsible for killing Dena," said Dena’s father Larry. 

Volunteers who make up the cold case task force say that boyfriend, his uncle, and his father are persons of interest in this case. 

The task force has served around 10 warrants in the past six months for telephones and DNA and are now hoping new technology can help them pull fingerprints from Dena's clothing. 

They say they're preparing to take their findings to prosecutors.

"There's more than one person involved. We'll see where we get to," said retired Sergeant Mike Huff with the Cold Case Task Force. 

Dena's parents hold a vigil and cookout every year on June 6th, share memories of Dena's life, and try to generate tips in the case.

"I'll either do it until I'm not breathing or until we get answers," said Dena’s mother Diana. 

If you have information, they have set up a tip line for the next 48 hours where you can call and talk directly to a cold case investigator. That number is (918) 388-7686.