At least three women were targeted at apartment complexes in Pike Creek, North Wilmington and Newark in the last two months.
Two of the women were abducted and robbed. The third scared the man away.
As long as he remains at large, officers want community members to pay attention to their surroundings and report anything that seems out of place.
"I think the biggest message right now is be that nosy neighbor. A lot of times people feel like they're being nosy or they're getting in other people's business. Right now we need people to be nosy," said Sgt. Wesley Reynolds with the Community Services Unit.
Police will also be offering personal safety tips during a presentation Wednesday night at 6:30 at the Hockessin Memorial Fire Hall.