NEW ORLEANS —A New Orleans man was sentenced Wednesday to serve 15 years in federal prison for helping his childhood friend, convicted serial killer Steven Earl Hardrick, execute two men after a carjacking and failed drug deal in October 2007.

Marvin Pierre, 27, cooperated with federal agents investigating Hardrick, and he “reign of terror,” according to court documents.

Hardrick was sentenced in March to spend 30 years in prison for a total of five murders: New Orleans Police Department Detective Thelonious Dukes, former Orleans Parish sheriff’s Deputy Dwayne Landry, a witness to a murder named Howard Pickens and two alleged drug dealers he carjacked and killed, Brett Jacobs and David Alford.

Eventually, Pierre and another of Hardrick’s friends, Robert Hart, pleaded guilty to assisting with the deadly carjacking.

Pierre, according to court documents, met Hardrick, Hart and another man on the evening of Oct. 24, 2007. Hart had arranged to buy high-grade marijuana from Jacobs at a price of $300 to $500. The two groups planned to meet in Lakeview for the drug exchange.

Hardrick had already, unbeknownst to the others, killed at least two people. On the night of Oct. 1, 2007, he shot Landry, a former deputy and Pierre’s best friend, and stole two of his guns. Less than two weeks later, on Oct. 13, he accosted Dukes outside of his home, forced his way inside and demanded: “Where’s the coke and money?” He killed Dukes, shot his wife in the foot, and stole two guns and a large sum of cash.

Pierre was suspicious that Hardrick might have been involved in Landry’s murder, his attorney Arthur Lemann IV said. Hardrick and Pierre grew up in the same neighborhood and ran together. But Hardrick served prison time, and came home changed, erratic. Pierre thought him dangerous, his attorney claimed, and began carrying a gun only to protect himself against Hardrick.

Yet Pierre and Hart both went willingly with Hardrick to Lakeview to meet the two men to buy the marijuana.

Alford and Jacobs arrived together at the Lakeview meeting spot in a Toyota Scion.

Hart got out of the car and spoke with Jacobs, who told him that the price for the drugs had been upped to $900. Hart returned to the car and told the others that the deal was off.

described his buddy’s killing spree as aBut Hardrick got out of the car with a 9mm Glock with an extended clip, which had been stolen from the former deputy he’d already murdered. He robbed the two men at gunpoint, stealing diamond earrings, a $6,000 diamond-encrusted watch and a handgun from Jacobs.

He separated the two men, then forced Jacobs back into the Scion and Alford into his own car.

Hardrick drove the car containing Alford and ordered Pierre to drive the other car along behind him. They went to a desolate road in eastern New Orleans. There, Hardrick forced both men out of the cars and ordered them onto their knees on the sidewalk. He shot them both multiple times in the back of the head.

Hart also fired one shot from his revolver, according to court records. Pierre would maintain throughout months of negotiations with federal investigators that he wasn’t even armed.

A man named Howard Pickens drove by on his way home from work, just before Hardrick pulled the trigger. Hardrick said he “couldn’t take any chances,” followed Pickens to his house and shot him twice in the head.

Hardrick gave Hart the murder weapon, who later handed it off to Pierre to hide.

All three men have pleaded guilty to various roles in the ordeal.

Hardrick, who admitted to all five murders, accepted a 30-year sentence, much to the dismay of the judge and his victims’ loved ones.

Though Hart and Pierre were scheduled to testify against him, the case against Hardrick lacked physical evidence and was fraught with recanted confessions. Prosecutors said they were uncertain of a conviction, so they grudgingly accepted the 30-year deal.

Hart pleaded guilty as an accessory and received a 17-year sentence. Pierre, too, pleaded guilty. Lemann wrote the court that there was no way his client could have predicted “Hardrick’s evil plan.”

Federal investigators, who compile sentencing suggestions, recommended that Pierre serve seven to eight years.

But after he entered his plea, and before he was sentenced, he admitted, for the first time, that he had been carrying a gun, a .38-caliber revolver, the night Jacobs and Alford were killed.

Prosecutors were incensed, and insisted that the sentence be upped to 11 years. Pierre, in an unusual concession, agreed to serve the 11 years, more time than the investigators recommended.

But at Wednesday’s sentencing hearing, the victims’ family told the judge they felt he’d gotten off too easy, Lemann said.

United States District Court Judge Sarah Vance agreed. She sentenced him to serve 15 years in federal prison — the maximum possible punishment for his charge.