document: John Bieniewicz, 44, was struck on Sunday during the game in a park.
  He was unconscious on the ground in the park when authorities arrived and died in hospital on Tuesday.
  Baseel Abdul-Amir Saad, 36, has been charged with assault with intent to do great bodily harm.
  But authorities say the charges could be amended following further investigation.
  Bieniewicz was an experienced referee who worked at all levels of competition, and a husband and father of two sons, according to media reports and a memorial page set up in his memory.
  "I speak for all his friends when I say we are devastated. Crushed. Just a senseless way for a great guy to go out," Bieniewicz's friend Jim Acho told the Associated Press news agency.
  Witnesses at the game in Livonia reported seeing Bieniewicz stop play to eject Mr Saad, who had complained about a call and was issued a second caution.
  Player Scott Herkes told the Detroit Free Press Bieniewicz was looking down and did not see the punch coming.
  "The ref did nothing to provoke this attack," Mr Herkes said. "I have never in my life seen something like this."
  Mr Saad reportedly left the field after the incident, and several players got the license plate number of his vehicle as he left.
  His lawyer Brian Berry told local media his client was co-operating and had voluntarily turned himself in to police.
  "Based on certain witness statements that have not yet been published, it is believed that the facts of this case have been mischaracterised," Mr Berry wrote in an email to the Detroit Free Press.
  "As tragic as this event is, we must keep open minds and listen and wait for all the facts of this case to unfold."
  It is the second such fatal case in as many years.
  In April 2013, a teenaged player punched referee Ricardo Portillo during a football game in Utah.
  The father of three died after a week in a coma. The teenager subsequently pleaded guilty to homicide.
summary: A football referee in the US state of Michigan has died after being punched in the head during an altercation with a player he was ejecting from a match, according to police and witnesses.