This article has been updated to include comments by Boston Police Commissioner Evans on WGBH's Boston Public Radio.

The number of murders rose in Boston last year, but Boston Police brought charges in fewer homicide cases than the year before, and the year before that.

In fact, statistics recently released by the Boston Police Department and reviewed by WGBH News show that in 2017 the BPD logged an arrest in only 46 percent of homicide cases – the lowest “clearance rate” in at least three years.

The findings, which refer only to clearance rates for the crime of homicide, come from numbers published by the BPD in its annual homicide reports for 2015, 2016 and its most recent 2017 report, published last week.

According to the 2017 report, there were 55 homicides in 2017. Two more homicides that occurred in prior years were counted toward the 2017 numbers, per FBI reporting requirements, making an official total of 57.

That’s compared to 49 homicides in 2016 — a 16 percent increase — and compared to 40 homicides in 2015.

But both the number and rate of homicide cases “cleared” by Boston Police officials declined over the same period.

In 2017, Boston Police Officers cleared 26 homicide cases, seventeen of those from 2017 and nine others from prior years.

That’s an overall clearance rate of about 46 percent, using the standard for calculating clearance rates outlined in federal crime reporting guidelines, compared to about 61 percent in 2016 and about 72 percent in 2015.

That makes last year’s clearance rate of 46 percent a significant drop, although the number is only slightly below the national average clearance rate for similarly-sized cities of about 49 percent, according to the most recent FBI data available.

Rachel Rodrigues, interim director of the nonprofit Louis D. Brown Peace Institute, dedicated to supporting families and communities affected by murder, said that a history of unsolved and un-charged murders has disproportionately left communities of color without answers.

“We want to push back on the answer that has been given to these communities a lot of times, which is ‘No one will come forward and tell us anything, and therefore we can’t solve it,'” Rodrigues told WGBH News.

“We know that when we see other murders that happen in other parts of the state — or something like the [Boston Marathon bombing], for example — those things get solved no matter what," she said. "They have ways of finding out who did this, and they won’t stop at anything until they find out.”

“We want to see that homicides get solved,” Rodrigues added, “and that families have some sense of answers.”

Prior to publication of this article Monday, BPD officials did confirm the accuracy of the 2017 numbers but did not respond to a request by WGBH News for comment on the apparent drop in the department’s clearance rate.

A 2017 academic paper by Northeastern Criminology professor Anthony Braga noted that BPD clearance rates had averaged about 47 percent between 2008 and 2011.

But those clearance rates began to rise, reaching an average of about 57 percent between 2012 and 2014, after the BPD implemented a new “clearance intervention” plan that included adding homicide detectives, a second victim-witness officer, and additional training in new technologies for homicide and forensic staff.

Speaking on WGBH’s Boston Public Radio on Tuesday, after this story was published, Evans said the 46 percent figure was “a little wrong,” claiming the department has a nearly-60 percent clearance rate. Evans said the Department’s clearance rate “over the last couple years has been almost 63 percent.”

But BPD spokesman Sergeant John Boyle, speaking after Evans’ appearance, did not dispute WGBH News’ findings about the 2017 clearance rate, and said that Evans had been referring to the department’s current clearance rate figures, as well as the average clearance rate for Evans’ tenure from 2013 to 2017.