Five years before Albert Bloch went missing in 2007, Jefferson Parish Sheriff’s Office Deputy Mark Hebert was chatting at Webster’s, an all-night diner in Metairie. The topic: how to get away with murder.

“He said, ‘If you put the body on a fresh grave’ ” and cover it back up with the dirt, no one would ever find it, Susanne Walker testified Thursday. “I thought, ‘Wow, it probably could work.’ ”

Bloch may be 4 feet under; nobody knows for sure. He disappeared in late 2007, and state and federal law enforcement searches have since come up empty: No financial transactions in his name. No visits to veterans hospitals. No arrests of the Vietnam vet and chronic alcoholic, who would be 68 today.

That’s because Hebert killed him, Assistant U.S. Attorney Stephen Parker argued Thursday before U.S. District Judge Jane Triche-Milazzo, during closing statements in an unusual federal sentencing hearing.

“Mark Hebert was given the perfect job to commit what he thought was the perfect crime. He had a job where he had absolute power over people on the street,” Parker said.

He said Hebert had a clear motive to kill Bloch: to cover up for charging thousands of dollars in racing car parts and other luxury items on Bloch’s bank card and signing his checks, and to gain possession of a replacement card issued after Bloch reported fraudulent charges on his old one.

When police first searched Hebert’s house in Covington and his vehicle as part of a different investigation, they found Bloch’s checks and bank statements, his ID, the new card and several big-ticket items Hebert had charged to Bloch’s account.

“He had everything Albert Bloch needed to carry on with his life,” Parker said, “and he knew that Mr. Bloch wasn’t going to be carrying on with his life.”

Hebert’s attorney countered that the government failed, over more than three days of testimony, to prove that the former deputy killed Bloch, or when, or to discount the statements of fellow bar patrons who claimed they’d seen Bloch, known as an all-day Budweiser drinker, after prosecutors say he was killed.

The bogus bank charges started a day after Bloch was hospitalized after wrecking his new Saturn sedan in the early morning of Aug. 2, 2007. Hebert was the lead investigator in the case, and someone handed him Bloch’s wallet.

Parker suggested that Hebert feared the fraudulent charges he ran up would land in Bloch’s mailbox, so he killed him.

One witness, a caseworker with Responsibility House, a homeless support group that helped Bloch find a place to live, said that when he tried to find the missing man, he noticed the lock on Bloch’s mailbox was gone and letters were spilling out.

“Somebody had to keep this crime from being reported. Otherwise, Mark Hebert’s life is over. He’s got a good job, he’s got a family, and you really don’t want to be a police officer in prison,” Parker argued.

He said, “Common logic dictates (the replacement card) was in Albert Bloch’s wallet on Oct. 1,” the day he last used it to withdraw cash at his favorite Metairie watering hole, Joe’s Caddy Corner.

“It had gone from Albert Bloch’s wallet to Mark Hebert’s. He’s using it. It had to come off the person of Albert Bloch. And it’s just a funny coincidence? No, that’s evidence.”

Milazzo said she would rule Tuesday on whether Hebert caused Bloch’s death, which could mean a life prison sentence or whether she will hand him a sentence only for the seven counts to which he pleaded guilty in November related to the fraudulent charges on Bloch’s account.

That still could mean a long stretch behind bars for Hebert, whom his ex-wife described as a hot-headed obsessive who turned from bodybuilding to racing cars. Prosecutors claimed the thefts were propelled by Hebert’s need for speed on the track.

As part of his guilty plea, Hebert admitted that he charged items on Bloch’s bank card before and after Bloch went missing at age 61. A new racing engine, high-priced cylinder heads, a pair of expensive GPS devices, a stove and grill set — all were bought by Hebert using Bloch’s card.

Hebert would transfer thousands of dollars from Bloch’s savings account to pay for still more purchases and cash withdrawals, often made while he punched the clock as a traffic cop.

At one point, while he was trying to cash a big check using Bloch’s ID, bank teller Melissa Gerstner told Hebert he didn’t match the photo of the older Bloch. “I said, ‘This is not the same person.’ He said, ‘Well, I’m his son,’ ” Gerstner said. “He said, ‘Well, he’s not doing too well right now.’ ”

By then, prosecutors said, Bloch was dead.

Hebert’s attorney, Davidson Ehle III, said outside the courtroom Thursday that Hebert stands by a statement he made to police that Bloch had become his racing sponsor, helping to bankroll his track hobby. He told his wife the same thing, she testified. Hebert also said he had returned Bloch’s checks to him about Oct. 15, 2007, two weeks after authorities say the Metairie man was last seen.

Ehle called no defense witnesses.

Hebert, 49, turned down an offer of 25 years in prison, a deal contingent on his turning up Bloch.

Lt. Gasper Migliore Jr., of the Jefferson Parish Sheriff’s Office, testified earlier Thursday that he conducted one of several interviews of Hebert, who “continued to deny his involvement in the disappearance of Mr. Bloch.”

Toward the end of that interview, he said, “Mr. Hebert — Deputy Hebert at the time — took a submissive stance and leaned forward and rested his arms on his legs. He looked at me, tilted at the side of his face and said, ‘If you had a body, I’d already be in jail.’ ”

Ehle tried to poke holes in a prosecution theory that Bloch was killed late on Oct. 1, possibly during a six-hour gap in cellphone and toll-tag activity for Hebert.

Ehle pointed to testimony that a now-deceased fellow patron recalled leaving Joe’s, probably the night of Oct. 2, and seeing Bloch playing video poker at the end of the bar. “See you tomorrow,” the fellow patron said.

“I asked every detective that took that witness stand to give me the evidence, tell me what it is, tell the court what evidence you have that Mark Hebert did anything to Albert Bloch on Oct. 1,” Ehle argued. “They have assumptions; they have theories; they have assertions. They didn’t have evidence.”

Prosecutors admitted they weren’t sure when Bloch was killed, but they noted a few time windows when Hebert might have acted, possibly while on duty late on Oct. 2.

Hebert was arrested at his Covington home in December 2007 on suspicion of burglarizing the Ford pickup of another man he had arrested in Jefferson Parish. Investigators picked up the connection to Bloch’s disappearance only after looking into that burglary and a theft from Ray Brandt Infiniti in Metairie.

Hebert was charged in 2008 with various thefts from at least three people in Jefferson. He pleaded guilty to simple burglary and two counts of malfeasance in office. He also was convicted of obstructing justice, access-device fraud and possession of stolen property in St. Tammany in 2009.

A federal grand jury indicted him in March 2013 on 60 counts related to the thefts from Bloch. He wasn’t charged with murder, however. Instead, the grand jury found that he “did kill, or participate in conduct that caused” Bloch’s death, as part of a fraud scheme.

Milazzo must find only that a “preponderance of the evidence” supports the allegations that Hebert caused Bloch’s death, not that he is guilty beyond a reasonable doubt. The lower standard, generally found in civil cases, means that she finds the allegations are more likely to be true than not.

Milazzo said that after her ruling Tuesday, she will order a new presentencing investigation before deciding on a sentence.

Follow John Simerman on Twitter, @johnsimerman.