>> obviously the scenario changed from a mental health observation to one of custodial. i mean, once they placed him under arrest then they started following procedures based on a typical arrest scenario. >> reporter: officers take lambert from outside the hospital to the police station. by the time they arrive he appears to be unconscious. an ambulance was called, but lambert could not be revived. his family has filed a $25 million lawsuit alleging, quote, the officers' conduct constitutes murder saying excessive force and negligence contributed to his death. the south boston police department and the three officers involved have denied these claims. a statement from their attorney says in part, quote, we are vigorously defending the case. our position is reaffirmed by the reports of two independent well-qualified experts in the field. while taser logs appear to show the officers pulled the trigger at least 18 times in a span of 30 minutes with one of the officers using a taser 15 times.