HARTFORD, Conn. – The legal ordeal of four Boston men wrongly convicted of murder by a cabal of gangsters and corrupt FBI agents apparently ended Friday with a decision by the U.S. Department of Justice not to appeal their record wrongful-imprisonment verdict to the U.S. Supreme Court, lawyers involved in the case said Friday.

The government had not appealed by a 5 p.m. EST deadline Friday, which lets stand an August 2009 decision by the U.S. 1st Circuit Court of Appeals upholding what is believed to be the largest verdict ever awarded in a wrongful-imprisonment case: $101.7 million.

The four men spent decades in prison after FBI agents, in a scheme to cultivate mob informants, allowed the fabrication of evidence that led to the wrongful convictions for a 1965 murder.

The Justice Department’s decision not to pursue another challenge of the verdict — awarded in July 2007 in Boston by U.S. District Judge Nancy Gertner — is the latest in a half-century of legal developments arising in Boston about mob violence and shocking corruption by key figures in law enforcement. In its opening lines, Gernter’s decision spoke of “egregious governmental misconduct” and the FBI’s “callous disregard” for the four victims, referred to throughout as “the scapegoats.”

Barring unexpected legal developments, the judgment will be divided among Joseph Salvati, Peter Limone Sr. and the estates of the other men, Henry Tameleo and Louis Greco Sr.

All were convicted in 1967 of the 1965 murder of Edward “Teddy” Deegan, a small-time thug killed in Chelsea, Mass.

A sensational series of legal developments starting in the late 1990s proved that the men had been framed by mob turncoats with the knowledge of agents at the highest levels of the FBI.

Three of the victims were reputed organized crime figures in Boston and are believed to have been framed to settle old disputes. Salvati, who had no links to organized crime, was wrongly implicated in the murder because he borrowed $400 from one of the turncoats and did not repay it quickly enough.

The FBI agents named in the wrongful-imprisonment case were the same figures implicated two decades later in what became a sensational attempt by members of Boston’s notorious Winter Hill gang to take over a significant portion of the U.S. parimutuel gambling industry.

Oklahoma tycoon Roger Wheeler was one of those shot to death in a conspiracy by then-current and retired FBI agents and mobsters in the takeover attempt.

Salvati’s lead attorney in his lawsuit against the federal government was Hartford lawyer Austin McGuigan, who said Friday he was encouraged by the government’s decision not to appeal.

The bench trial before Gertner in 2007 amounted to a painstaking recreation of events that began with the murder of Deegan.

Salvati and the other victims produced as evidence hundreds of previously secret FBI reports showing that their innocence was known to the FBI within minutes of Deegan’s slaying.

Deegan’s real killers were the mob turncoats that the FBI was trying to recruit as informants: Joseph “The Animal” Barboza and James Flemmi.

After Deegan was killed, FBI agents allowed Barboza to implicate the innocent men on the condition that he become a cooperating witness in a series of mob prosecutions. Barboza agreed on the additional condition that his partner be kept out of the Deegan case as well.