A new report from Boston’s former police commissioner criticizes Amherst and UMass police for how they handled last march’s blarney blow-out — a student party that spilled into the town and led to 55 arrests.

Thousands of students swarmed to last years Blarney Blowout, a well-known annual party that also attracted many people from out of town. The event got out of hand, when the crowd, many of whom were drinking heavily, threw bottles, and destroyed property. UMass and Amherst police came under scrutiny for approaching the melee with riot gear and pepper spray, and for making a large number of arrests. So UMass chancellor Kumble Subbaswamy hired former Boston police commissioner Ed Davis to investigate what happened. In his 65 page report, Davis acknowledges the challenge of that day and night, but says the university should have taken steps to tamp down the party to begin with — by limiting guests on campus and working more closely with local bar and liquor store owners. He also says town and university police need to coordinate emergency responses more centrally.

“And then, when it comes down to the actual event, and the bottles and rocks start being thrown, if you don’t have sufficient officers, you should pull back, and wait, until there are sufficient officers there, even though there’s a threat of violence,” Davis says.

Police chiefs from both Amherst and UMass –speaking at a press conference with Davis — disagreed with that assessment.

“For what we faced out there, for my perspective, if we had pulled back, community members in danger….would have been negligent, and could have resulted in individuals being injured,” says UMass Police Chief John Horvath.

Police did agree that more officers should be available during parties likely to escalate. UMass and town leaders also say they will follow Davis’ advice to train officers in community policing, to better enforce under-age drinking policies, and to host more non-alcoholic late-night activities on campus.