Norton Shores police said Wednesday that Jessica Heeringa's blood has been found at the gas station where she was abducted from last month.
Police Chief Daniel Shaw tweeted that DNA analysis confirmed the blood.
Heeringa, 25, has been missing since April 26. She was ending her shift as a clerk at the Exxon Mobile station when she disappeared.
The station didn't have a security camera and there were no signs of a struggle or robbery.
Herringa's purse and other personal belongings were found in the station. The cash register was untouched.
Police have released a description of a silver minivan and a man seen in the area.
Shaw says about 2,000 tips have been received in the case.