There are nearly 60 cases of major unsolved crimes in the Halifax area; most of those cases are murders, with the oldest dating back to 1955.

The rate in which such crimes have been solved has been criticized over the years, but police say the files come with many challenges.

Megan Adams, whose sister Kimberly McAndrew disappeared in August 1989, says she understands solving cold cases can take time.

“We understand how these investigations go. Do we think there have been, you know, wrong turns and false leads and all the rest of it? Absolutely. But at the end of the day, it’s still an open case.”

Cpl. Shawn Mason, who is in charge of the cold case unit, says more than 50 of the 59 cases are homicides.

“When the investigation was done at the time, they did an awesome job and they were good investigators,” says Mason of McAndrew’s case. “So, now they’re handing it off to me to expect to look at it and say, ‘well, what wasn’t done?’ And it’s tough to follow up on that.”

As an investigation grows older, Mason says it’s more difficult to crack the case as possible suspects die and witnesses move away.

However, with time also comes advances in technology and DNA testing; exhibits can be reintroduced to crime labs.

“When you have an exhibit or a swab - a blood sample that’s so small that you don’t think that will amount to anything – we’re getting it sent off to the lab now and they’re coming up with results,” says Mason.

He says investigators used new technology during a recent search in Shad Bay, N.S. which determined whether the ground had been disturbed.

“We used ground-penetrating radar on the weekend, which up to two weeks ago I had no idea that it existed.”

Tom Martin spent 15 years as a homicide investigator. He has since retired, but hasn’t forgotten about the cases.

“It’s a part of you. It becomes a part of you.”

Martin continues to keep a close eye on unsolved crimes in the city. He says the cold case unit needs experienced staff and resources are critical.

“It’s the ultimate crime and we have to put – we, as society – have to put resources into finding out those who walk among us who are responsible for these types of crimes, because that just cannot get a pass.”

Stephen Kimber, a journalism professor at the University of King’s College, has asked some tough questions while writing articles on the number of unsolved murders.

“I think it’s important because if you don’t raise those questions then it just slides under the radar, and we talk about it in the Tim Hortons and those sort of things, but we don’t really confront it,” says Kimber.

Mason says he has seen some major changes since he was assigned to the unit two years ago, such as advances in technology.

“We’re going in a direction which will certainly be helpful to a lot of these unsolved homicides.”

Meanwhile, Adams holds onto the hope that her family will one day receive some answers about her sister’s disappearance. Until then, she says she has learned bitterness is too high a price to pay.

“At the end of the day, you need to appreciate the family that you do have and you need to be thankful for the investigators that have the case, that you know they want to solve this too.”

With files from CTV Atlantic's Jacqueline Foster