(CNN) -- Jessica Heeringa, 25, was due to close the Michigan gas station where she was working alone as a cashier at 11:30 p.m. Friday. But at 11:15, police got a 911 call that the station was unmanned. When police responded, Heeringa was gone.
"Something very bad happened," the police chief of Norton Shores, a community of 22,500 near Lake Michigan about 40 miles west of Grand Rapids, told CNN affiliate WOOD-TV.
"This was an abduction, not just a missing person," Chief Daniel Shaw told the station.
"There was nothing disturbed inside the store. There was no sign of a struggle or a robbery had occurred," Shaw told the station. Heeringa's purse was left in the store, and her car was still there, WOOD reported.
Heeringa last served a customer about 10:50 p.m., police said.
"Between the time that last purchase was made and the time that the customers came in and found the store empty is when Jessica was abducted," Shaw told WOOD. "We have spoken with the person who made the purchase there and cleared them of any wrong. And unfortunately, they didn't see anything that would lead them to believe there was something going on at the store that was leading to that abduction."
The chief told the station police are looking for the driver of a silver minivan who was seen in the store's parking area late Friday.
Shaw described him as a white male, between 30 and 40, with wavy hair parted in the middle, according to WOOD. The van could have been a Chrysler Town and Country, he told the station. The store did not have security cameras, leaving police with few other clues.
"We are desperately looking for additional information," he told WOOD on Monday morning.
Heeringa's family and friends were posting missing posters around the area, and a Facebook page was set up for people to offer clues or support.
"We are searching! Hang tight! The whole Country wants you home!" said a Facebook post from Monday morning. Tips had come in from as far away as New Jersey, Missouri and Arkansas, WOOD reported.
Heeringa is described as 5 feet, 1 inches tall, 110 pounds with blond hair, blue eyes and wearing wire-rimmed glasses. She has a 3-year-old son, her family told CNN affiliate WZZM-TV.
Besides local police, the county sheriff's department and the Michigan State Police were involved in the investigation, according to local media reports. The FBI has also been contacted, the reports said.
"We've got a team of detectives and investigators on staff all day and night to track down those leads," Shaw told WOOD.
"We are very concerned. It's been too long," Heeringa's grandfather, Roman Homrich, told Mlive.com on Monday.
Heeringa's mother, Shelly Heeringa, told WZZM that she thinks her daughter's abductor was a past customer who knew Jessica and the store.
"She's very helpful, that's why I think he lured her out of the gas station," the mother told the station. "He knew there wasn't security cameras."
People with information that may help find Heeringa are asked to call the Norton Shores police at 231-733-2691.