LACEY, Wash. -- Police are still hunting for the person who attacked a woman when she was walking on a Lacey trail and now police want DNA samples from two dozen people, including those who aren't accused of any crimes.

Lacey police have identified two dozen persons of interests in the case of a St. Martin’s University student who was attacked and raped in April on a popular trail near campus. Police said the rapist used a stun gun during the attack.

Police said out of the 170 tips that came in about the case, detectives have narrowed it down to 24 men. They will soon be contacting the men by going to their homes and asking some for voluntary DNA samples.

“That would be one of the easiest ways to eliminate somebody, would be to get a voluntary DNA sample," said Lt. Jim Mack of the Lacey Police Department.

Detectives plan on sending the DNA samples to a lab to run tests for a possible match to the DNA from the rapist -- already collected at the crime scene.

"I think if it helps narrow it down and help find the guy who raped the girl, I'm all for it you know," said Kylie Nelson of Lacey.

Despite their progress, police said they can still use the public's help. Anyone with information should call 911.