No one has been held accountable for the murders of 27-year-old roommates Nicole Glass and Melissa Mason.

The two women were found strangled to death inside their Phoenix, Arizona home on December 3, 2010.

No police suspects have been disclosed. And there is no apparent motive.

Nicole and Melissa had been roommates on and off for approximately three years. They shared the single-story, brick home that Nicole purchased in 2006.

Their bodies were discovered inside the house when a concerned friend stopped by because she had not heard from Nicole.

"Her girlfriend called when Nikki didn't show up to exercise that morning, Nicole's mother Rachel Glass said, adding that Nicole was a strong girl, despite her 5-foot-4 frame, who lifted weights and ran on the treadmill for an hour a day.

When no one answered the door, the friend walked around the outside of the house and peered through a back window, finding the bodies of both women lying lifeless on the floor.

Phoenix investigators say Melissa Mason’s boyfriend was the last person to see the girls alive. He visited them at their home the evening of Dec. 2, then left around 8:00 p.m.

Detective Tobi Myers said both women sent text messages from their phones after Melissa's boyfriend left.

"Since they were only text messages and not phone calls (meaning no one heard their voices) we consider [him] the last person to see or talk to the girls," Myers said.

Melissa's mother Sandra Minjarez said the last text sent from her daughter's phone was to her boyfriend shortly after 10:00 p.m.

He didn’t call back until after midnight, Minjarez said.

“That’s when he tried to call her and the calls would go straight to voice mail.””

Investigators said there was no sign of forced entry and that the women were known to leave the front door unlocked. There was nothing to indicate a violent struggle or fight prior to their deaths, Myers said.

"But how can you tell because there was nothing to be pushed around?" Glass asked, adding that Nicole had moved the furniture for ongoing renovations.

"They were doing the floors," Glass said. "She had every bit of furniture pushed to the sun room in the back. The only things in the living room were the two couches and the TV."

Glass said workers had been in and out of the house for about a week.

Det. Myers confirmed that certain personal items left unaccounted for could have been stolen; however, other high dollar items still remained in the house when investigators arrived.

Police have not released whether the women were killed by ligature or manual strangulation. No drugs or alcohol were found at autopsy for either of the women.

The mothers of both Nicole and Melissa say they struggle to find answers to why anyone would want to take the lives of the lives of their daughters.

According to Glass, Nicole was excited about her life and the new plans she had for her home.

"She bought this house when she was 23. She loved it. This was her pride and joy," Glass said.

At the time of her murder Nicole was a junior at the University of Phoenix. She was taking classes online, pursuing a degree in communication.

“I think what she wanted to do was to have a business, something to do with beauty and fashion,” Glass said.

Nicole and Melissa had been friends since 2006 when they met working as bartenders at a Phoenix strip club. The girls continued to bartend in separate clubs up until the time of the murders.

"I wasn’t happy with it. But what can you do?" Glass asked. Glass said it was difficult for her daughter to walk away from money she earned. Nicole worked during the daytime and typically left work around 5:00 p.m.

Melissa had already graduated, in 2004, from Pima Medical Institute in Tucson, where she worked as a dental assistant before moving to Phoenix.

“She wanted to become a dental hygienist, but there was a four-year waiting period,” her mother said. “In the meantime she needed to get a job, but it was hard to get a job as a dental assistant because they were not giving her enough hours.””

The case turned into a triple homicide when it was discovered that Melissa was two months pregnant.

Her mother later found out that Melissa was waiting until Christmas to share the news.

“When I was going through her things, I found the pregnancy test and it said ‘Melissa, plus one, I love you, Merry Christmas,’” Minjarez said. “I didn’t get to give Melissa a baby shower.””

Minjarez also learned that Melissa and her boyfriend, the child’s father, had been to the doctor for a sonogram.

“The next day, that’s when they killed her,” she said.

Melissa’s boyfriend took and passed a polygraph examination and was very cooperative in the investigation, according to Det. Myers.

Myers said no “stalker” types or seriously concerning persons have been identified for either of the women. Police have not ruled out scenarios involving more than one perpetrator.

"Nicole was a gorgeous girl,” Glass said. “Sometimes I just think this is a bad dream. I need justice. I need them to find out what happened.””

Minjarez described Melissa as very loving.

“She never even raised her voice at me. I’m not saying she was a saint,” Minjarez explained, “she just loved her sister so much, and me. She would shower me in gifts for Mother’s Day, for my birthday. I’d say, ‘Don’t spend all your money on me.’ We were very close. I even went to the place she was cremated. I just wanted to be with her.””

“We had no closure. It’s like they’re dead so it’s not important.”

Det. Myers said she intends to continue working on the murders within her department and has no current plans of turning the case over to the cold case unit.

Glass and Minjarez recently announced an increased reward of $10,000 for information leading to an arrest in the case. The increased reward was made possible by realtors, Chad DeVries and Chris Arpelli, who donated their commissions from the sale of Nicole’s home.

Anyone with information concerning the case is asked to contact Silent Witness at (480) 948-6377 or toll free (800) 343-TIPS.