A judge lifted a court order banning the media from naming 16-year-old Jimmy Owens, who killed Derek Whyteside with a single blow on the day he left secondary school.
Passing sentence on Thursday, Judge Paul Glenn accepted that Owens, of Malinslee, Telford, Shropshire, did not intend to kill when he struck Mr Whyteside, who was armed with a knuckleduster, once on the head after approaching him from behind.
The teenager's father, William Owens - who struck Mr Whyteside on the head as the 42-year-old lay dying with a fractured skull - admitted affray and was jailed for 20 months at Stoke-on-Trent Crown Court.
Judge Glenn, who condemned "despicable" mobile phone pictures of the victim taken before he was put in the recovery position, praised the efforts of the schoolboy's mother to help the injured man, who died in hospital 36 hours later.
But the judge told the juvenile defendant that although he was not responsible for stealing the missing bikes, he had not "done the decent thing" in helping to recover them.
The court heard that another youth was cautioned for theft.
The judge said of the fatal attack on June 18 this year: "Derek Whyteside had decided to go and look for those who he plainly considered to be involved (in the theft).
"He was plainly ready for trouble."
Jimmy Owens was found guilty of murder after a trial at Stafford Crown Court which started in October.
The jury was told that he would be guilty of murder if he had intended to cause really serious harm when he attacked Mr Whyteside.
Passing sentence, Judge Glenn told him: "You emerged from the bushes and struck him from behind with the bat.
"You aimed at his head. You used significant force. He had no chance to take evasive action - it was a vicious blow delivered in anger."
Jailing William Owens, 41, of Boulton Grange, Telford, Judge Glenn told him: "Your part was, frankly, outrageous. Your involvement and the effect on the community is so serious only custody is appropriate."
The judge said Australian-born Mr Whyteside - who had "demons" involving alcohol and drugs - had behaved badly on the day in question but had paid a "terrible and totally unjustified price" for doing so.
Mitigating for Jimmy Owens prior to sentencing, defence counsel Patrick Harrington QC said the younth had previously been chased by Mr Whyteside, and that provocation had played a role in the incident.
"The court may feel that this was a 16-year-old boy that left school that day with aspirations and ambition and did nothing wrong to cause the trouble that came to him," he told the court.
In a victim impact statement read to the court on behalf of Mr Whyteside's partner, Michelle Beddall, she said: "I am having to go through living hell because they acted like animals and can't face up to what they have done.
"I hate what they have done to me and my kids."