MEXICO CITY (AP) — Mexican President Andrés Manuel López Obrador promised Monday that justice will be done in the case of a French restaurant owner who was found murdered over the the weekend.

López Obrador compared the case to last year’s killings of nine U.S. dual-nationals in northern Mexico, claiming “practically all” of whose alleged killers in that attack have been arrested.

“Work is being done on a thoroughgoing investigation. One has to have faith that we will be able to make progress with that investigation,” López Obrador said. “Nobody will be allowed impunity.”

Authorities said evidence indicates dual French-Mexican citizen Baptiste Jacques Daniel Lormand set out late last week to sell bottles of high-end wine or liquor, accompanied by a Mexican partner. They drove in two vehicles to the city's rural south side.

Both appear to have been met by people who stole the bottles and killed them. Their bound, bloody bodies were found in a vacant lot Saturday.

“The investigation indicates that they wanted to rob them of the merchandise that they were offering for sale,” Mexico City police chief Omar Garcia Harfuch said Sunday. Harfuch wrote later that a suspect had been arrested in connection with the murder and the circumstances of the arrest “confirmed” the robbery theory.

Harfuch and others had been eager to deny the murder had anything to do with two problems that plague many business owners in Mexico City: kidnapping and extortion, in which the perpetrators frequently identify themselves as members of drug cartels to scare their victims into paying.

But the police chief conceded there have been a number of cases on the city's south side in which people have been attacked while trying to buy or sell goods offered on the internet.

“We have identified a modus operandi of setting up fake transactions of goods advertised to the public, in which at the moment that a face-to-face meeting is set up to supposedly carry out the transaction, the sellers are attacked and sometimes killed,” said Garcia Harfuch.

French Ambassador Jean-Pierre Asvazadourian wrote in his Twitter account that “like our entire community, I am saddened by the murder of our countryman.”

Lormand ran a Mexican-themed restaurant in the city's upscale Polanco neighborhood, far from the hardscrabble, rural borough on the south side where he was killed. He apparently drove there of his own volition.

A spokesman for the Mexico City prosecutors' office suggested the coronavirus pandemic may have hit the restaurant business so badly that Lormand turned to selling expensive liquor, or that normal channels for distributing high-end wine or liquor may have been disrupted by the coronavirus outbreak.

“The economic situation has of course been substantially altered by the pandemic, and in many cases people have turned to other activities, and other types of methods like deliveries have fallen into disuse,” said prosecutors' spokesman Ulises Lara.

It was unclear why the thieves had killed the victims if the intent was just to steal the merchandise.

Mexico security analyst Alejandro Hope offered one theory in a newspaper column Monday, entitled “Life is worthless,” noting that about nine out of 10 murders in Mexico go unpunished.

“This tragedy has a structural cause, impunity,” Hope wrote in the newspaper El Universal. “In Mexico, killing is very cheap. The probabilities that a killer will be punished are very low.”