Updated

Violent crime dropped 6 percent in 2010, marking the fourth straight year of year-to-year declines, while property crime was down for the eighth straight year, falling 2.7 percent, the FBI reported Monday.

Nationwide, there were an estimated 1.2 million violent crimes in 2010 and an estimated 9 million property crimes.

An aging population and continued high rates of imprisonment for criminals are helping to drive down crime rates, said James Alan Fox, a criminologist at Northeastern University.

Robbery fell 10 percent, rape dropped 5 percent, and murder, non-negligent manslaughter and aggravated assault fell more than 4 percent.

Each category of property crime offenses decreased in 2010. The largest decline, 7.4 percent, was for motor vehicle thefts. Burglaries decreased 2 percent and larceny-thefts declined 2.4 percent.

"The last thing we should do is get complacent and say `mission accomplished,' and so let's transfer resources away to other areas," said Fox. "You don't solve the crime problem; you only control it. Without policing and crime prevention, the numbers can go back up."