03/07/2013 at 08:00 AM EST
Reluctantly believing she is dead, the family of Michelle Parker, the Florida mom who vanished
after appearing on The People's Court
in 2011, filed a wrongful death lawsuit Thursday against her ex-fiancé, Dale Smith
, whom they believe was responsible.
Parker's family claims Smith knows what happened on Nov. 17, 2011, the day Parker was last seen alive.
"The family doesn't want to believe that Michelle is dead, but they believe that she is," their attorney, John Morgan
, tells PEOPLE. "This is a case that has gone cold, so a civil case is the only way that Michelle's family will finally get answers. Given the passing of time, as well as some evidence we have discovered, we believe that Dale Smith is responsible for her death."
Smith's attorney tells PEOPLE that he sympathizes with the family's loss, but maintains his client's innocence.
"After a very thorough investigation by us and the police, there has been no evidence that ties Dale Smith to her death," says Mark NeJame. "He has previously cooperated with law enforcement and has spoken to them four times. Obviously, the family of Michelle Parker has suffered a tragic loss and our hearts go out to them, but to sue Dale will bring them no closer to discovering what happened to Michelle."
For 16 months, Parker's family has sought answers about what happened to the 33-year-old mom. Little evidence has been uncovered, aside from her cell phone, which was found in an nearby lake
just days after her disappearance.
Police named Smith as their prime suspect, but he has not been formally charged in her disappearance.
Parker was last seen dropping her 3-year-old twins off at Smith's home on the same day that the estranged couple appeared on The People's Court
, haggling over a lost engagement ring. (They had taped the show weeks earlier.)
"He gets pretty malicious and vindictive, especially when he's been drinking," Parker claimed on the show. "He shouldn't have put his hands on me." Parker's Hummer was later found abandoned in an Orlando apartment complex parking lot.
"I want my baby back," Parker's mother, Yvonne Stewart, said in a press conference last year. "I need closure."
Her attorneys say the only way she'll get that closure is through a lawsuit. "She deserves answers," says Morgan. "We think that this is the best way for her to get the answers that she deserves. No mother should have to go through this."