PHOENIX (KSAZ) - Unsolved since December 2010, the murders of Nicole Glass, Melissa Mason and Mason's unborn child.
The roommates were strangled to death in their Phoenix home and police never determined a motive, but Rachel Glass has refused to give up.
"People have moved on, but I haven't because I can't let go of this until I find out the truth," she said. "My daughter deserves that."
Rachel Glass says just recently she received information that her daughter, Nicole, may have been a confidential informant for the Phoenix Police Department before her murder.
The 27-year-old was involved in a large drug conspiracy and money laundering case, but the family doesn't know exactly who she may have been talking to police about.
"I believe this was a hit on my daughter," Rachel Glass said.
In the lawsuit, filed Tuesday morning, attorneys claim Nicole was used to gather information about the criminal activity, dangerous individuals.
"We believe there will be information that comes to light that indicates that police did not take adequate steps to protect her," Attorney J. Scott Halverson said. "At this point, though, the lawsuit will enable us to find out more information. It gives the gateway to find out what really happened. There are individuals in the police department that know the details of her work for them."
For Rachel Glass, who has held vigils and waited years for answers, this may be her best lead yet.
"I hope that it opens the door to finding the answers about the circumstances surrounding my daughter's death," she said. "Somebody needs to be held accountable for this."
The Phoenix Police Department released the following statement to Fox 10 on the lawsuit:
"The Phoenix Police Department has been aggressively investigating this homicide since it occurred in 2010. Although the case remains open, to date, investigators have not found any evidence to support this recent claim. The Phoenix Police Department will remain focused on the facts surrounding this case and we are committed to solving this crime."