One year after her body was found in the woods near Orangeville, Ont., police continue to search for Sonia Varaschin's killer.

The 42-year-old nurse was first reported missing in late August of last year. Her body was discovered Sept. 5 in a wooded area not far from her home in Orangeville, about 80 kilometres northwest of Toronto.

Police have collected evidence from three different crime scenes and in May requested DNA submissions from a list of men who knew Varaschin.

"I think it's important for the killer to understand we have your DNA and it's only a matter of time before we find out who you are," Const. Peter Leon told CBC News in May.

'Still a very active case,' police say

Now one year after her body was found, Varaschin’s killer remains free but Ontario Provincial Police Sgt. Pierre Chamberland said the work of compiling evidence continues.

"It’s still a very active case," said Chamberland. "CSI technology science is not at all how you see it on television. It’s very time-consuming. We’re still collecting evidence as a matter of fact. So all of that has to be looked at, analyzed and ultimately classified."

So far police will only say there are persons of interest in the case and that they have gathered evidence from three separate crime scenes.

Earlier this year in an interview with CBC News, Varaschin’s mother Michelle expressed frustration at the progress of the investigation.

"I find I feel worse now than I was right at the beginning, because not knowing what happened," she said.