The number of homicides in Massachusetts fell to a 10-year low in 2015, which law enforcement officials attribute to a crackdown on gang violence, drug trafficking and illegal guns.

There were 133 homicides in the state last year according to figures provided to The Boston Globe by state police and departments in Boston, Worcester, Springfield, and Pittsfield. State police investigate all homicides except those occurring in those four cities.

There were 146 homicides in Massachusetts in 2014. The highest number in the past decade was 220 in 2010.

Boston Police Commissioner William Evans pointed to youth outreach programs, community walks, and initiatives aimed at seizing illegal guns as contributing factors to fewer killings in Boston.

Some even credited record-setting snowfall in 2014 with helping to keep crime rates low.