Referee hostility
Referees are encountering high levels of hostility (Getty)

A man who fatally injured a referee with a single blow as he was about to be shown a red card during a recreational match has been handed a minimum of eight years in prison.

Bassel Abdul-Amir Saad, 37, who lives in Dearborn, Michigan, pleaded guilty to involuntary manslaughter after hitting John Bieniewicz, 44, in the neck during a game in June 2014.

Bieniewicz died two days later.

Saad had originally faced a charge of second-degree murder, but Wayne Circuit Court Judge Thomas Cameron accepted Saad's plea of manslaughter.

The referee's widow, Kristen Bieniewicz, said Saad's actions brandished a red card at the hearing on Friday.

"The one final thing that I want to do is I would like to serve Mr Saad with the red card that he was entitled to," said Mrs Bieniewicz. "It's murder. It will always be murder in my eyes," she said to the judge.

Saad expressed remorse for his actions, saying: "I'm so sorry from the bottom of my heart. I'm going to continue to pray for him and his family."

Judge Cameron denounced Saad's actions. "You have through a childish senseless act destroyed two families," he commented.

Saad will be eligible for parole after eight years, but could serve 15 years in jail and faces deportation to Lebanon, his home country. The court also ordered him to pay Bieniewicz's funeral costs, which are more than $9,200.

The levels of hostility directed at football referees is alarming and highlights the escalation of violence in the game.

Last year, Ghanaian assistant referee, Kwame Andoh Kyei was beaten to death during a second division match between Gold Stars and Naa Joe United.

In 2013, Brazilian official Otavio da Silva was stoned to death and decapitated after he fatally stabbed a player for refusing to leave the pitch.

In 2012, Dutch assistant referee, Richard Nieuwenhuizen was also punched and kicked to death by several players.