A surge in mail thefts around the county, a doubling of car break-ins in downtown Santa Rosa in December and a spree of burglaries in Petaluma were among the upticks in property crime that kept Sonoma County law enforcement busy in 2013.

Despite those resource-sapping spikes, the Sheriff's Office and Sonoma County's largest police department, Santa Rosa, reported an overall decrease in property crimes between 2012 and 2013.

The number of property crimes decreased 8.1 percent in Santa Rosa and 3.5 percent in Sonoma County.

Regardless, law enforcement said they had plenty to do.

"It sure didn't feel that way to me," Sheriff's Property Crimes Sgt. Mike Raasch said of the decline. He said 2013 was a busy year, perhaps because many of the cases detectives dealt with were particularly involved.

In one time-consuming case, he and other detectives identified more than a dozen suspects in a string of mail thefts going back as far as September.

Two suspects have been arrested, but law enforcement is still seeking the others.

The decline for the Sheriff's Office and Santa Rosa, as well as the state of California, followed an uptick in such crimes in 2012.

Between 2011 and 2102, Santa Rosa saw a 3 percent increase in the number of property crimes — larceny, burglary and auto theft. The sheriff's jurisdiction saw a 7.7 percent increase during the same time period, according to FBI statistics.

That uptick came at the end of a period in which property crime rates had decreased to historic lows. Researchers with the Public Policy Institute of California pointed to the shift of inmates from state prisons to county jails as a factor in the increase.

In 2011, the state, under court order to reduce populations in its crowded prisons, undertook the shift of lower-level inmates, commonly known as realignment.

However, local law enforcement and probation officials said there is not yet enough information to tell what impact, if any, realignment has had on crime rates.

Santa Rosa Property Crimes Sgt. Phil Brazis said it is hard to connect realignment to an increase in property crime because, unless someone is caught in the act, there's no way of knowing who is committing the crimes.

Whatever the reason for the 2012 increase, it appears to have reversed last year in Santa Rosa and the Sheriff's Office jurisdiction.

According to preliminary statistics provided by the departments, auto thefts in Santa Rosa declined from 316 in 2012 to 309 in 2013. In the sheriff's jurisdiction, they declined from 11 in 2012 to 10 in 2013.

Larceny in Santa Rosa decreased from 2,777 incidents in 2012 to 2,560 in 2013. The Sheriff's Office saw incidents of larceny decrease from 856 to 794 between the years.

Burglary decreased by 12 percent in Santa Rosa, from 725 to 638, but increased slightly, by 2.6 percent, in the sheriff's jurisdiction.

And in contrast to its overall decrease in burglaries, Santa Rosa saw an unusual doubling of vehicle break-ins in downtown Santa Rosa in December, Brazis said.

Such crimes are often more frequent during the holidays, Brazis said, but this year, the surge was unusually high.

In December, police counted 21 vehicle burglaries and thefts in the downtown area. That's compared to 9 last December. Thefts have continued into January and February, Brazis said.

"The numbers are concerning for me; we're trying to come up with leads," he said.

He urged people to conceal valuables or keep them out of their cars entirely.

In Petaluma, meanwhile, property crimes increased in 2013, with notable spikes in vehicle thefts and burglaries.

Petaluma Lt. Tim Lyons attributed some of the city's crimes to "roving bands" of criminals, who may target Petaluma over other Sonoma County cities because of its position as a "gateway to the Bay Area."

In Rohnert Park, where the massive Graton Resort & Casino opened in November, motor vehicle thefts and burglaries also rose slightly between 2012 and 2013, according to preliminary statistics provided by the Rohnert Park Department of Public Safety. Car thefts increased from 59 to 64, while burglaries increased from 118 to 136.

The increase could be attributed, at least in part, to an influx of people coming into Rohnert Park, Lt. Jeff Taylor said.

"Rohnert Park is now a destination place," he said.

Overall, property crime decreased by about 11 percent in the city.

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