Missing Littleton woman Charlene Voight still missing after 4 weeks

LITTLETON, Colo. -- Charlene Voight disappeared four weeks ago under very suspicious circumstances, and Denver7 has uncovered documents that show Voight's boyfriend has threatened to kill others in the past.

Jeffrey Scott Beier has not been named as a suspect or person of interest in Charlene Voight's disappearance; however, he is in jail in an unrelated sexual assault case involving a different woman.

Denver7 legal analyst David Beller said that case gives Littleton detectives time to investigate what happened to Charlene.

"They can really make sure they have a very solid case to put in front of a jury if it ever gets to that," said Beller.

Beller said that with no body, it it is significantly more difficult to prosecute a case, though not impossible.

"There are many, many different forms of evidence. A body is just one of them," said Beller.

Denver7 has discovered a 2007 case file showing Beier's ex-wife told police he had "beaten her up several times," and Beier plead guilty to threatening to kill her.

But that is not all -- records state another woman accused Beier of assaulting her in 2009, claiming they had been dating and that he "threatened that if I were to go to the police, he would kill me and my family."

Beier also plead guilty and served time in a domestic violence case involving Voight in 2013. In 2012, she stated that she was in fear for her life.

Still, Beier's lengthy history of domestic violence doesn't prove he did anything to Charlene, but it could be used in court to show a pattern.

"We don't necessarily know where the body is or what happened to her," said Beller. "So the circumstances of these other cases are incredibly important to law enforcement."

It is not unheard of for prosecutors to move forward in a murder case without a body, though it can take much longer to build a case.