A 78-year-old retired police officer from Nevada has been sentenced to 46 months in prison for assaulting a 73-year-old man on a Hawaii- bound cruise ship.

In handing down the sentence this week, U.S. District Judge Jill A. Otake stated that John McAvay of Henderson had “sucker-punched” Michael O’Connor as he tried to leave a restroom stall on a Star Princess cruise ship bound for Hilo from Los Angeles. Several months after the incident, which occurred in October 2018, O’Connor died in a California rehabilitation facility.

Also, McAvay was sentenced to one year of federal probation for assault resulting in serious bodily injury. He was found not guilty of involuntary manslaughter, a charge brought by prosecutors who claimed the pulmonary embolism that killed O’Connor was tied to the assault in the restroom.

Otake wrote there is “no doubt” that McAvay acted “cowardly, reprehensibly and despicably.” She noted that while the court did not struggle with any question related to McAvay’s behavior, instead the most difficult question was a scientific and legal one related to a pulmonary embolism that apparently caused O’Connor’s death.

The FBI and U.S. Coast Guard Investigative Service conducted the incident’s investigation. O’Connor told investigators that on Oct. 23, 2018, he was using a closed-door stall in a restroom on the seventh deck of the ship when he was “confronted by an unknown agitated male” as he tried to leave the stall. O’Connor had not been drinking alcohol prior to the assault, according to court documents.

McAvay and O’Connor exchanged words in the doorway of the stall, before O’Connor tried to walk away. O’Connor said Mc­Avay hit him in the head as he walked past him, according to court documents.

A witness told investigators that he was washing his hands at the restroom sink when he heard the two men, situated behind him, arguing. The witness told investigators that when he turned to throw away a paper towel he saw McAvay hit the other cruise ship passenger in the head with his closed right fist.

O’Connor, the witness said, dropped like a “dead body,” hitting his head onto the toilet a couple of times and then rolled onto the floor, according to court documents. Another witness told investigators that O’Connor was bleeding from his forehead when he told the witness that he had been hit by someone “trying to get in” while O’Connor was “trying to get out.”

O’Connor sustained a cut to the side of his head and two small lacerations on each earlobe. He told the ship’s doctor he did not lose consciousness.

McAvay, meanwhile, told investigators he “cold-cocked” O’Connor after banging on the door to the stall and arguing with the man. A witness overheard McAvay tell his wife that O’Connor had kicked the back of McAvay’s leg before McAvay punched O’Connor.

O’Connor told investigators that the day after the assault he had difficultly moving limbs and maintaining his balance. He sought medical assistance and was admitted to the ship’s sick bay for monitoring. Throughout the day O’Connor’s condition deteriorated. After experiencing tremors, in­stability on his feet and weakness in his arms — symptoms consistent with a secondary brain injury, according to court records — by nightfall, he was vomiting, experiencing neck pain radiating to the top and back of his head and involuntary leg spasms.

A military helicopter airlifted O’Connor to Hilo Medical Center, according to court records. There, doctors determined O’Connor needed trauma care, and O’Connor was transported to The Queen’s Medical Center in Honolulu where he was hospitalized for a month. After leaving Queen’s, O’Connor was taken to a rehabilitation facility on the mainland.

As a result of the assault, O’Connor suffered from “serious cognitive and physical impairments — including confusion, memory loss, and immobility” until he died Feb 6, 2019, according to court documents.

McAvay was arrested Oct. 28, 2018, after he was identified by another cruise ship passenger as the man who hit O’Connor. When asked by FBI agents why he did not tell authorities about the incident, McAvay said, “I didn’t really think, in my mind, that I did anything wrong, and, you know, I thought I didn’t want to get involved in a big deal … I’ve been around courts and the legal system … and I just didn’t want to — for it to go any further.”

Acknowledging that he could have walked away from the alleged kick, McAvay described the assault as “just a self-defense, gut reaction.” Investigators did not find any bruising on McAvay’s leg.

A doctor who examined O’Connor, who had been a cancer patient and had a heart condition, characterized the matter as a “weak homicide case” and testified that he could not tell from an autopsy examination whether cancer or immobility was more likely to have caused the pulmonary embolism. Regarding her ruling on that question, Otake wrote, “This was not an easy decision, and if the burden of proof were lower than it is, the outcome could have been a different one.”