NIAGARA FALLS, N.Y. - Reliable data is hard to find, but it's probably fair to say that tens of thousands of homicides remain unsolved all across the United States at this very moment.

Some of them may have happened this year or this week. These investigations are fresh, and police may soon gather enough evidence to make an arrest. But other homicides happened many years ago, maybe decades ago, and even the active investigations have mostly faded from the public's memory.

That's perhaps one of the biggest fears for the friends and family of Theresa Insana, a Niagara Falls native who was killed in Las Vegas in 2004. Her case has been covered extensively in the media over the years -- including a Dateline NBC feature in 2011 -- but it has not received much attention lately.

That's changing.

The cable channel Discovery ID will be replaying Theresa's Dateline piece on May 8 at 9 p.m. Another cold crime show has taken interest in the case, and new DNA testing will be completed.

Grace Carducci, Theresa's close childhood friend, can feel the momentum.

"We believe this is the year where things are really going to come to pass," Carducci said, "and I have a feeling that we're finally going to find out who did this to Theresa."

Theresa Insana, with her parents Joseph and Ann-Marie. 

Insana was only 26 years old when she disappeared in Las Vegas on Oct. 26, 2004. The Niagara Falls High School and Binghamton University graduate had moved out west shortly after college to pursue a career in sales. On Nov. 1, 2004, not even a week after she went missing, her body was found, and the Las Vegas Police Department launched an investigation.

More than 13 years have passed. Las Vegas Police have not abandoned the investigation, and new detectives are now looking at the case, according to the Insana family.

But it's been a very long and frustrating 13 years. Earlier this month, Theresa's parents, Joseph and Ann-Marie, and her siblings, Maribeth and Christopher, came to Channel 2's studios in downtown Buffalo to tape another interview. They were joined by Carducci, who was also interviewed on Dateline in 2011.

From left to right: Grace Carducci (Theresa's childhood friend), sister Maribeth Insana and brother Christopher Insana

Six years after the Dateline NBC episode first aired, the Insana family still keeps in constant contact with Las Vegas Police.

"It's a little disheartening, all that has happened and all that continues not to produce some kind of answer," Joseph Insana said. "I think there's probably reasons for that, because people just won't come forward with it."

Joseph and Ann-Marie are hopeful the year 2017 will bring them answers in their daughter's case. 

Maribeth Insana recently created a Facebook page in her sister's memory, hoping to take advantage of the new social media world to make connections in the investigation. More than 20,000 people have already viewed the Facebook page, she said.

The goal is for the page to reach people far and wide, especially in Las Vegas.

"It's super hard to believe that this much time has passed," Maribeth said. "We haven't given up hope, and we believe that person is still out there and they had some connection to Theresa. We're just waiting for that moment that they are going to crack, or someone they know to crack, to give us some information."

The Las Vegas Police Department did not immediately respond to requests for an update on the investigation, but the Insana family confirms the department has been very responsive to their needs. The family is asking the public to either contact them directly through the Facebook page or call Las Vegas Police if they have any information.

"That would be a great help," Joseph Insana said. "Even the smallest thing."

Carducci said she's hopeful the new DNA testing, as well as the public attention on local and national television, will lead to a breakthrough.

"We believe in the heart of hearts that the perpetrator is out there, the perpetrator knew Theresa and at some point, somebody's going to talk," Carducci said. "We have faith in that. And we will never give up until that happens."