BOSTON (AP) -- A young son of a man beaten to death at his son's youth hockey game was so overcome with grief that he crawled into his father's casket during his wake, a friend said.

''It was a very sad situation,'' Gene Ellison, a friend of Michael Costin, told ABC's ''Good Morning America.'' ''It was a very difficult moment for a lot of people.'' He said the wake was held Monday.

Costin, 40, of Lynnfield, died two days after being beaten unconscious in front of children on Wednesday. The single father of four had recently won custody of all his children. A funeral service was scheduled for later Tuesday in Lynnfield, a Boston suburb.

Thomas Junta, 42, of Reading, was released on $5,000 bail Monday after pleading innocent to manslaughter in Costin's death. Junta's lawyer, Thomas Orlandi, said his client was acting in self-defense, and that the victim started the fight.

''There are two sides to every story,'' Orlandi said at the arraignment. ''Mr. Junta ... has bruises to his ribs. He has bruises and cuts on the inside of his legs where he was defending himself from where he was kicked.''

The fight started during an informal practice at the Burbank Ice Arena in Reading, 15 miles north of Boston.

Costin was on the ice supervising the players -- including his three sons and Junta's son. Junta, watching from off the ice, became concerned that the playing was getting rough, his lawyer said.

When Junta yelled at Costin to stop the rough play, Orlandi said, Costin ''skated over to Mr. Junta, swore at him and said 'That's what hockey is all about.'''

Prosecutors said Junta ran onto the ice screaming at Costin, and that the two men wrestled. A rink manager ordered Junta to leave, but he came back in.

''The two men then squared off, exchanged blows. And Mr. Junta, who stands about 6 feet 1, weighing 275 lbs. -- approximately 100 lbs. heavier than Mr. Costin -- quickly gained the upper hand,'' Middlesex County Assistant District Attorney Gerard Butler said.

If convicted, Junta faces up to 20 years in prison.

In arguing it was self-defense, Orlandi mentioned Costin's police record, which included multiple convictions for such charges as weapons possession and assaulting a police officer. Prosecutors said Junta also had a record, having been charged in 1992 with assault and battery. There was no finding in that case.

Authorities had sought $25,000 cash bail, but the judge agreed to a lesser sum because of Junta's family and clean recent record. A truck driver for 13 years, Junta has a son, 10, and a daughter, 16.

Speaking on NBC's ''Today'' show Tuesday, Augustine Costin blamed his son's legal difficulties on personal and family problems.

''He wasn't a criminal, he wasn't a bad kid. He had a drinking problem, and there was a problem with the family,'' Costin said. ''And all the reason why he was in jail was because he was trying to get his children back because the courts gave the wife custody.''

Augustine Costin himself was convicted of manslaughter in the stabbing death of another son, Dennis, 17, about 25 years ago, The Boston Globe reported Tuesday.