By Lori EhdeIt’s been five years since 20-year-old Carrie Nelson was murdered while working in the office of the Blue Mounds State Park.Since then, authorities have tested DNA of more than 400 possible suspects — more than any other case in Minnesota — but her killer remains at large.Now investigators are releasing more details about her death, and they and her family hope a new reward will lead them to a murder suspect.They’re offering $50,000 for any information that leads to an arrest."I’m glad they’re trying again," said Carrie’s mother, Nan Karr Kaufenberg. "It’s good that they’re trying to get leads. … She deserves this — to find out what happened and to find the person who did this so they can pay the penalty and we can put this to rest."Carrie Nelson was working alone behind the counter in the park office on May 20, 2001, when she was beaten to death.Investigators are now being more specific about how she died and the evidence they found that might link them to a suspect.For one thing, she was beaten with a rock that was on display in the office. It’s a distinctive rock that a DNR officer spotted a week later in a nearby stream. "We determined it is the rock, because there were rock chips left behind at the scene," Rock County Investigator Jeff Wieneke said.The killer also left behind fingerprints, but they don’t match any in the national criminal database of those who have been or are currently incarcerated.Investigators also say the killer left behind DNA evidence on a watch found in the park office.With the release of this evidence and the reward, investigators say they're just a phone call away from solving the case."We do have some suspects, but most of them have been cleared," Wieneke said."We’re hoping new information will bring someone forward who hasn’t come forward before, if not for the money, but to clear their conscience."Individuals with information about the case are encouraged to call the Bureau of Criminal Apprehension's Cold Case Unit at 651-793-7000 or contact the Rock County Sheriff's Office at 507-283-5000. Wieneke said the reward was officially offered Friday, and already information is coming in."The case is also being reviewed by two new BCA agents to make sure we’re not missing anything in our investigation," Wieneke said. "I hope it works out for us."The $50,000 is being offer through a program with the BCA that accepts donations from Minnesota corporations. That amount had been offered in the first year after Nelson was murdered.The current offer is valid only for the next 90 days. Carrie’s father Stan Nelson said he’s glad the case has been resurrected."I think it’s a positive thing that we’re shining a little light on it again and bringing it back to people’s awareness," he said."We’re hoping that some leads turn up. We would like to see whoever is responsible caught and held accountable."He said his daughter’s brutal murder has pointed to a need for people to refocus their attention away from violence on more positive, peaceful things."People keep saying we need to catch the killer so we can have closure, but I spend very little time thinking about that. I spend more time thinking about what I can do," he said."I appreciate the efforts of all those who are trying to catch Carrie’s killer, but I would encourage people to focus on what they can do get at the roots of violence. … We need to be mindful of what we hold in our hearts as human beings."