Criminals are watching Sonoma County's vacation homes, sheriff's detectives warn, saying burglars have been hitting clusters of unoccupied houses and making off with TVs, other electronics and furniture.

Sonoma County Sheriff's detectives have received 52 reports of burglarized vacation homes since September, Property Crimes Sgt. Mike Raasch said earlier this week.

From Sonoma Valley to the Russian River and Bodega Bay, thieves have entered homes by forcing open windows or sliding doors. They appear to be targeting one area before moving on to another. In some cases, the same home has been hit twice or even three times.

"We need people to be more diligent about their surroundings" and report suspicious activity, Raasch said.

Raasch would not say how the burglars might be finding the vacant vacation homes, citing the ongoing investigation. But some managers of vacation rentals point to increasingly popular websites where homeowners advertize their properties to travelers for short-term stays. Such sites often list where homes are located and when they're available, said Thera Buttaro, a vacation rental manager and Real Estate broker in Bodega Bay. She says her company takes care to never list such information online, but still, two of the rental homes she manages were burglarized in the past three weeks.

Bodega Bay, particularly the residential community Bodega Harbour, is the latest in a series of hot spots the burglars appear to be targeting. Seven burglaries have been reported there recently. Other areas targeted include Guerneville, with 15 reported burglaries, Cazadero with nine, Forestville with seven, and Boyes Hot Springs, Monte Rio and The Sea Ranch with two each.

"I hope we catch them soon," said Buttaro. She became aware of the problem about three weeks ago when her vacation rental company's operations manager went to a Bodega Harbour vacation home to prepare for visitors arriving later that day. When he arrived, he found that the TV in the living room had been disconnected and removed, Buttaro said.

Buttaro sent out a notice almost immediately to warn the property owners she works with.

Several days later, she learned that more area homes that she didn't manage in the area were burglarized. And two days after that, another of her properties was targeted.

"For the most part, they got in, got what they wanted and didn't do much damage," she said.

Ellen DeProto, manager of Russian River Vacation Homes in Guerneville, has seen four of the homes her company manages burglarized, starting around Christmas. She also sent out an alert right away so that homeowners could take extra steps to protect their property.

DeProto said the thieves seemed to be targeting neighborhoods, not just vacation rentals, in Guerneville and Forestville. In many cases, nonrentals, such as vacant second homes, were also burglarized, she said.

"Whoever is doing it clearly knows the area," she said.

Raasch, however, did not see a connection. Home burglaries happen all the time, he said, but he has not noticed a significant uptick recently.

Detectives have some leads in the burglaries but no official suspects, Raasch. That's after hours of combing through surveillance video.

"We're pounding the pavement, doing a lot of follow-up, but we haven't cracked the case yet," Raasch said.

However, detectives think at least half the burglaries have been committed by the same person or people, based on the techniques used to get into the homes and the items taken.

Three women were arrested in December in connection with three similar burglaries that happened in Santa Rosa, Healdsburg and Windsor in November and December, Raasch said. They have since been released, but detectives do not believe the women are responsible for the latest spate of burglaries.

Raasch said solving the case could hinge on alert homeowners watching out for suspicious behavior, like a strange car or person lingering near a house, and reporting it to the Sheriff's Office at 656-2185.

Raasch also encouraged homeowners to protect their rentals by locking them well, making them looked lived-in, and asking neighbors to keep an eye out for something amiss.

You can reach Staff Writer Jamie Hansen at 521-5205 or jamie.hansen@pressdemocrat.com. On Twitter at @JamieHansen.