Is Michigan kidnap-attempt suspect connected to Jessica Heeringa disappearance?

Jessica vanished, and cops say they think the single mom was abducted. But they don't know who might have done it, or where she might be.

Jessica was working alone at a gas station in Norton Shores, a bedroom community on the shore of Lake Michigan.

Police say the night of April 26, 2013 appeared to be routine, until a guy in a silver minivan parks behind the building. The van was recorded on surveillance video from the cameras at the pumps.

The gas station manager and her husband just happened to be driving by and told cops something just didn't seem right.

"What they saw was a male figure at the rear of the van with the back hatch open. The figure shut the hatch door and then quickly opened it back up again," said retired Norton Shores Police Chief Dan Shaw. "It appeared to them that he was moving something in the van, like he was adjusting something."

Police say the manager and her husband watched, first thinking that Jessica might be stealing.

"So when they saw this person behind the store, they did not see the door open, did not see Jessica," said Shaw.

"She was looking at a car that was a silver Chrysler Town and Country minivan. There's 15,000 of those minivans in Michigan alone," said Crime Watch Daily Correspondent Billy Jensen. "That's not even counting the surrounding states."

Sometime after 11 p.m. a customer walked in, didn't see anyone working and called 911. When cops arrived Jessica Heeringa was gone.

In the back room investigators found her jacket and her purse containing more than $400. The cash register was untouched. The trash can was by the door.

"That could have meant that she was ambushed when she was going outside, perhaps to open up the door to take out the garbage, and she was struck potentially over the head and then dragged into this van, and then taken away."

Police mounted a massive search using helicopters and K-9s, but the trail went cold -- and so has the case.

The lead detective thinks Jessica is still alive and she's being held against her will.

"Nobody has found a body or remains or clothing or anything else of evidence to suggest that Jessica is deceased," said Norton Shores Police Lt. Michael Kasher. "I have to go on the assumption and belief that she is still alive somewhere."

While there were security cameras outside, there were none inside that might have captured the abduction.

Jessica's mom Shelly testified before Michigan legislators demanding a law requiring gas stations install cameras inside to protect employees working alone.

Detectives reportedly have at least six possible persons of interest.

One might be Brad Mason, suspected of kidnapping and sexually assaulting two women resembling Jessica. Almost a year after Jessica vanished, Kalamazoo cops shot and killed Mason as they tried to arrest him in connection with those kidnappings.

In a dramatic new development, just this week police arrested a different kidnap suspect who drives a silver van. Jeffrey Willis is charged with the kidnapping of a 16-year-old girl.

Prosecutors say Willis had a secret compartment in his van containing handcuffs, syringes and a liquid they say might be a sedative.

The prosecutor says he's looking into whether Willis could be connected to the unsolved murder of another young woman, Rebekah Bletsch, who was shot on the road while she was jogging.

Could this be the break cops need related to the case of missing Jessica Heeringa?

"I understand that everybody's looking for that link, everybody wants myself or someone to come out and say Yes, we have that link, we've made that nexus -- we have not," said Muskegon County Sheriff Dean Roesler.

Willis is being held on a million-dollar bond.

Willis is facing one charge of kidnapping, one charge of assault with a dangerous weapon and two felony firearms counts. He has not yet pleaded, and is expected to appear in court in the next two weeks.