The Pre-Operation Briefing: On the evening of March 15, 1968, Medina briefed Charlie Company on the next day's operation. Multiple soldiers testified that Medina told them to kill everything that moved in the village, including women, children, and livestock. Medina denied giving explicit orders to kill civilians, leading to the central dispute of the My Lai case.

Personal Killing of Vietnamese Civilian: Medina admitted to shooting a Vietnamese woman at close range during the operation, claiming he thought she was reaching for a weapon. Other witnesses testified that the woman was unarmed and posed no threat. This admission made Medina one of the few officers to acknowledge personally killing a civilian.

Failure to Stop the Massacre: Even accepting Medina's claim that he did not order the killing of civilians, witnesses testified that he was present in the village during the massacre and was aware of the mass killings occurring. As company commander, he had both the authority and the duty to order a cease-fire and stop the killing, but he took no meaningful action to halt the massacre.

Court-Martial and Acquittal: Medina was charged with responsibility for the murder of 175 Vietnamese civilians as the commanding officer. Leading defense attorney F. Lee Bailey represented him, arguing that command responsibility required direct knowledge and failure to act, which could not be proven beyond reasonable doubt. Medina was acquitted in September 1971.

Falsification of Body Count: After the operation, the official after-action report from Charlie Company claimed 128 enemy killed in action against only 3 weapons recovered. As company commander, Medina bore direct responsibility for these grossly falsified reports that characterized a civilian massacre as a successful combat engagement.

"Mad Dog" Reputation: Medina was known to his troops by the nickname "Mad Dog" for his aggressive leadership style. His emphasis on body counts and aggressive patrolling reflected the broader command culture in Vietnam that prioritized kill statistics over civilian protection.

Paul Meadlo's Accusation: After losing his foot to a land mine the day after the massacre, PFC Paul Meadlo screamed at Medina: "God punished me, and God will punish you." Meadlo later testified on CBS that Medina's briefing left no doubt that they were to kill everyone in the village.

Post-Acquittal Life: After acquittal, Medina resigned from the Army and moved to Marinette, Wisconsin, where he worked in various civilian jobs. He rarely spoke publicly about My Lai and lived in relative obscurity until his death in 2018 at age 81.