Denver experienced more murders last year – more than at any point in the last decade.

In 2015, there were 51 murders – a 65 percent jump over the year before. Retaliatory gang violence, early in the year, helped to push the murder number to a 10-year high. The East Colfax, Cole, and North East Parkhill neighborhoods saw the most violence.    

The problem in Denver mirrors a national trend. Many big cities across the country saw a spike in murders, from Milwaukee to Dallas to New York.

But Denver’s murder rate -- 7.8 deaths per 100,000 people -- is still much lower than similarly-sized Baltimore, which had a murder rate of 55.3 deaths per 100,000 people

Criminologists don’t have a good explanation for why murders have increased in so many cities, as other crime rates continue to fall.