There have been 23 homes burglarized in a 10-day period, most of which are in the Browns Valley neighborhood. The break-ins were reported Oct. 17-27.
Police believe the robberies involve either one person or a small group of burglars.
A woman named Monica said she went out to run errands and came home to find that someone had visited her bedroom.
"And that's immediately when I realized the room had been ransacked. All the drawers were open," the woman said.
She said the crooks stole all her jewelry, including her wedding ring, along with expensive perfume and handbags.
Monica said she called loved ones, who told her to get out of the home.
"It didn't even dawn on me to get out of the house," the woman said.
In each case, police say, a young, clean-cut man comes to the door and says he's looking for a friend -- or he's selling magazines.
"What they're really doing is trying to see if there's anyone home or not. If they don't find anyone home, then they're basically going around to the side of the residence, going through a side gate, going to the rear of the residence and forcing entry," Jeff King from the Vacaville Police Department said.
Police said the homes that were hit are in middle- to-upper-class neighborhoods and that they all had unlocked gates and no barking dogs.
So far, nobody has been hurt and no weapons have been reported in the incidents.
Monica said she's since had an alarm installed and finds herself more suspicious of people nearby.
"Everybody that I see walking around looks a little suspect, because you just don't know. They haven't caught anybody, so you just don't know," she said.
This article originally appeared on KCRA.com.