A federal judge on Friday slashed more than a dozen years off the 17 1/2-year prison sentence of former city technology vendor Mark St. Pierre, citing his “substantial” assistance in helping federal prosecutors secure the conviction of “another individual,” almost certainly a reference to former Mayor Ray Nagin.

U.S. District Judge Eldon Fallon, in a one-page order, agreed with a motion filed by federal prosecutors to reduce St. Pierre’s sentence. He settled on five years.

St. Pierre, who was convicted on 53 counts of conspiracy, bribery and wire fraud, already has served most of that time. He reported to prison in Fort Worth, Texas, nearly three years ago. That means, assuming he is given credit for good behavior, he could be eligible to move to a halfway house in a few months. Inmates typically serve their final six months or so in a halfway house.

Now 51, St. Pierre was convicted of paying bribes and kickbacks totaling roughly $860,000 to city technology chiefs Greg Meffert and Anthony Jones, gaining millions of dollars in public work in return.

St. Pierre, who bankrolled trips for Nagin and his family to Hawaii and Jamaica, was not called to testify against the former mayor at a trial this year in which Nagin was convicted on 20 of 21 federal corruption charges and later sentenced to 10 years in prison. But federal prosecutors credited St. Pierre for the help he gave them following his conviction in 2011.

Presumably, though he did not testify, St. Pierre helped to corroborate Meffert’s assertions that Nagin knew St. Pierre was underwriting the trips for his family, as well as lawn care for the Nagin home on Bayou St. John and cellphone service for the mayor’s children.

Nagin testified that he had no idea St. Pierre was his benefactor.

The sentence reduction came a day after Meffert, 49, delivered an abject apology in federal court and received a 30-month prison sentence from Fallon, less than a third of the 96-month term that sentencing guidelines dictated in his case.

In his order on St. Pierre, Fallon said that if he “were to deny any reduction, the sentence of Mr. St. Pierre would not be proportional to the sentences imposed for similar conduct by other individuals arising out of the same factual scenarios.”

“I thought that it was the right thing to do by the government and the court,” Eddie Castaing, St. Pierre’s lawyer, said. “It was an act of humanity by the government and the court, and it was in accordance with the law. Mark will never repeat his mistakes, and one day, he will be a contributing member to the community again.”

Castaing said St. Pierre had agreed to drop his appeal more than a year ago to show he was accepting responsibility. He also agreed to begin cooperating with the government.

Nagin is due to report to federal authorities Monday to begin the 10-year prison sentence that U.S. District Judge Ginger Berrigan handed him in July.

Fallon on Thursday ordered Meffert to report to federal prison Jan. 3.