In a grim reckoning of the opioid epidemic, State Police announced Thursday that they had investigated 755 fatal suspected heroin overdoses in 2015, more than two per day.
Of the overdose victims, almost 80 percent were men. On average, victims were 36 years old.
The year-end statistics do not include Boston, Worcester, and Springfield, the state's three largest cities, and as a result understate the magnitude of the problem.
In August, the state Department of Public Health said that 1,256 Massachusetts residents had died in 2014 after overdosing on opioids such as heroin and painkillers, an 88 percent increase from 2012. The toll continued to climb in the first half of 2015, public health officials said.
"This is the worst year I've ever seen," said Joanne Peterson, executive director of Learn to Cope, a support network for families. "Unfortunately, I'm not surprised at all."
Peterson said that despite growing public awareness of the problem, painkillers continue to be overprescribed, putting many people on the road to a devastating addiction.
"It starts with the pills, and then goes to heroin," she said.
According to a new Boston Medical Center study, more than 90 percent of people who survived a prescription opioid overdose were able to obtain another prescription for those same drugs. Most got it from the same doctor who gave them the first prescription, the study found.
Middlesex County had the most overdose victims, with 142, followed by Essex, Bristol, and Plymouth counties. Those figures were skewed by the absence of Boston, Worcester, and Springfield data but show that the problem of heroin addiction "knows no geographic boundaries," State Police said in announcing the year-end figures.
State Police began tracking overdoses more closely last December and do not have comparable statistics for 2014.
While the state medical examiner's office determines the official cause of death, State Police use evidence found at the scene, including drug paraphernalia, and statements of witnesses, to make preliminary determinations.
State Police investigated 64 homicides in 2015, down from 72 in 2014. They made an arrest in 47, for a 73 percent clearance rate.
As with drug overdoses, State Police have jurisdiction over homicides in every municipality in Massachusetts except for Boston, Worcester, Springfield, and Pittsfield.
Homicides dropped sharply in Boston in 2015, from 54 to 40, through Dec. 30.
State Police tallied 3,865 arrests of drivers for operating under the influence of alcohol or narcotics. They did not immediately have comparable statistics for 2014, but a 2013 Globe story said arrests had risen sharply the year before, from 3,884 to just over 5,000.
State Police also cleared more than 4,000 warrants, including 45 people on murder warrants.
"The men and women of this department worked around the clock, every day and night, to protect the lives, safety and property of everyone who lives, works and travels through our state," Colonel Richard D. McKeon said in the announcement.