There have been 43,792 homicides in Venezuela since 2007, according to the violence observatory, compared with about 28,000 deaths from drug-related violence in Mexico since that country’s assault on cartels began in late 2006.

Caracas itself is almost unrivaled among large cities in the Americas for its homicide rate, which currently stands at around 200 per 100,000 inhabitants, according to Roberto Briceño-León, the sociologist at the Central University of Venezuela who directs the violence observatory.

That compares with recent measures of 22.7 per 100,000 people in Bogotá, Colombia’s capital, and 14 per 100,000 in São Paulo, Brazil’s largest city. As Mr. Chávez’s government often points out, Venezuela’s crime problem did not emerge overnight, and the concern over murders preceded his rise to power.

But scholars here describe the climb in homicides in the past decade as unprecedented in Venezuelan history; the number of homicides last year was more than three times higher than when Mr. Chávez was elected in 1998.

Reasons for the surge are complex and varied, experts say. While many Latin American economies are growing fast, Venezuela’s has continued to shrink. The gap between rich and poor remains wide, despite spending on anti-poverty programs, fueling resentment. Adding to that, the nation is awash in millions of illegal firearms.

Police salaries remain low, sapping motivation. And in a country with the highest inflation rate in the hemisphere, more than 30 percent a year, some officers have turned to supplementing their incomes with crimes like kidnappings.