Violent crime in the United States dropped last year, according to FBI statistics released Monday, but the murder rate climbed during the last half of 2011.
It was the fifth straight year that the overall violent crime rate, which includes murder, rape, robbery and aggravated assault, fell. Compared to 2010, the rate nationwide for that category dropped 4 percent last year.
But criminologists found reason for concern in trends in the latter half of the year. Steep declines in murders and robberies in the first six months of 2011 were offset in the second half of the year. Murders were 5.7 percent lower from January through June 2011, but only ended the year down 1.9 percent -- meaning that they increased from July through December.
The drop in robberies, which started off the year down 7.7 percent, cooled off to finish only 4 percent lower than the previous year.
"It worried me a little bit, because maybe we've hit bottom and are beginning to inch upward," said Northeastern University professor of criminology James Alan Fox. "It's the crime rate limbo stick: There's only so low that you can go."
Murder across the country picked up 1.9 percent from July to December last year, according to Fox's estimate.
Still, cities like Houston, Baltimore and St. Louis registered far fewer homicides than in 2010. Houston had 198 compared to 269; Baltimore went from 223 to 196; St. Louis cut its total from 144 to 113.
Moving in the other direction were cities like San Jose, Calif., where murders practically doubled, 20 to 39. In Memphis, they increased from 89 to 117 and Detroit's total rose to 344 from 310, according to the FBI's stats.
The murder rate in small towns with populations less than 10,000 however defied the national trend and spiked more than 18 percent. Some experts told HuffPost it was an insignificant change, because the total number of murders were spread out over huge geographic areas.
"I don't want to downplay dead bodies," John Jay College of Criminal Justice professor Michael Walker told The Huffington Post. "But the odds of being a murder victim in that demographic is very slight."
In another category, property crimes, such as burglary, larceny theft and auto theft were slightly down compared to the previous year, falling 0.8 percent, according to the report.
Despite the fragile American economy, the number of property crimes continued to decrease, too. Like violent crime, the improvement was modest compared to 2010, when the drop was 2.7 percent and 2009 when it fell 6.1 percent.
"Everyone expected them to go up because of the frustration and economic turmoil," said Carnegie Mellon University professor Alfred Blumstein, who studies crime data.
Innovations in car security systems have been one of the main forces pushing down the overall crime rate.
The FBI didn't release the number of crimes in each category -- the bureau's Preliminary Uniform Crime Report only describes the percent change compared to previous years. A more detailed report will be published in the fall. FBI officials also declined to offer explanation for the year-to-year trends.