An important consideration for the Barnstable police is whether the attackers were law enforcement officials.
Although Alves said that none of the attackers self-identified themselves as officers nor did he see any badges, others at the bar Wednesday night told him his assailants were participants at the narcotics investigators convention being held this week in Hyannis.
Alves also said anyone working in bars for years, as he has, is able to identify off-duty police officers.
"They are big, strong and fit, and they are in groups of four, six or eight," Alves said.
The New England Narcotic Officers Association is based in Framingham and comprises 1,200 active and retired local, state and federal law enforcement professionals from New England.
The president of the association, Westminster Police Chief Salvatore Albert, did not respond to an email sent by the Cape Cod Times seeking comment on the Hyannis incident. Ashland police Detective Matt Gutwill was identified by a woman answering the phone at the association's office as the association's media contact at the convention. Contacted by telephone, Gutwill said he knew nothing about an alleged violent incident involving association members.
Anthony Pettigrew, a spokesman from the U.S. Drug Enforcement Administration in Boston, said his office would look into the Hyannis incident, but he declined to make any further comment.
Speaking about his personal feelings, investigating other police officers is not enjoyable, Balcom said.
"But we have a job to do," Balcom said. "The bottom line is, you have someone with broken bones in his face."
Charges may go beyond simple assault and battery, Balcom said.
If Alves was kicked, charges would include assault and battery with a shod foot, MacDonald said.
If the DJ's injuries are considered significant, further charges may be brought against the perpetrators, the police chief said.
Times staff writer Doug Fraser contributed to this report.