Boston's police commissioner squared off in court Tuesday with the leader of the city's largest police union over a plan to have 100 officers wear body cameras, as lawyers for each side accused the other of having "unclean hands" in a long-simmering dispute over police accountability, reports WCVB .

A pilot program was scheduled to start last week. But after no officers volunteered, Commissioner William Evans ordered 100 officers to wear the cameras. That prompted the Boston Police Patrolmen's Association to ask a judge to issue an injunction to halt the program until a new agreement can be negotiated.

Union President Patrick Rose testified Tuesday that the city violated its agreement with the union when Evans assigned officers to what was supposed to be an all-volunteer program. Rose acknowledged that he told members not to volunteer for the program before the union had reached an agreement with the city. But he insisted that once the agreement was reached, he encouraged officers to volunteer.

Evans said he wants the program to begin next week and believes it's within his authority as police commissioner to order officers to wear the cameras. He said renegotiating with the union and soliciting volunteers at this point "will only further delay the start of the program."