PARIS — If you listen to his neighbors in one sleepy little Normandy town that could be just about anywhere, Maxime Hauchard was nothing if not a good boy. For the postwoman, mouth agape learning the news, and the dismayed local grandmothers paraded unassuming and guileless before French news cameras and radio microphones all day Monday, it just couldn’t be.

But French authorities have confirmed that Hauchard, a 22-year-old French convert to Islam, is indeed one of the unmasked executioners in the so-called Islamic State’s latest gruesome massacre video.

A good boy gone terribly wrong? In the video released Sunday, Hauchard stands beside other ISIS henchmen, similarly attired in black caps and sand-colored camouflage, wielding a knife as he clutches a bent, balding Syrian man, primed for execution. The 16-minute clip portrays the decapitation deaths of 18 Syrian government military personnel and appears to show the severed head of American hostage Peter Kassig at the feet of a hooded British ISIS militant notoriously known as Jihadi John.

Hauchard is the first of the unmasked executioners in the ISIS video to be positively and publicly identified, although French authorities have said a second young French Muslim convert’s appearance may be authenticated shortly. As intelligence services around the world are working to identify any other foreign fighters among the band of killers in the gory new video, speculation also surfaced that another of the killers is 20-year-old Welsh jihadist Nasser Muthana, but that has yet to be confirmed.

Indeed, analysts agree one of the video’s key functions for ISIS is to illustrate how far the group’s seductive reach is extending globally. As France took in the shock news that one of its own sons may be a throat-slitting, decapitating terrorist, the Islamist specialist Romain Caillet told Le Monde, “In putting forward soldiers from the four corners of the world, Da’esh [as the French call the group, using the Arabic acronym for ISIS] is looking to create a ‘United Colors of Jihad’ effect. The message is simple: there are hundreds of Jihadi Johns.”

Before his bloody star turn Sunday, Maxime Hauchard’s story was, given the context, frighteningly banal. Born in Normandy to Norman-born parents, he was raised a Catholic along with a sister four years his junior in Le Bosc-Roger-en-Roumois, an inland town of 3,200 some 20 miles south of Rouen.

One of the local reporters who descended on the village en masse Monday described, in Le Parisien, a pastoral town where “every street corner smells of woodfires and cowsheds, far from the urban projects.” Hauchard’s parents’ white house was shuttered against the media onslaught Monday. They reportedly left Sunday night on word of their son’s bloody ISIS cameo.

By all accounts, Hauchard was handy at fixing scooters. He even registered a business selling spare parts out of his parents’ home in 2010. He and a neighbor friend worked for a time in a pizzeria in a nearby town. His only known run-in with the law was a 300-euro fine for failing to stop at the scene of an accident and lacking insurance. And as neighbors have unfailingly emphasized in local media interviews, he was supposed to be a nice guy.

“He mowed the lawn, chopped the wood. When he partied a little with his friends behind the house, everything always went smoothly,” one neighbor identified only as René told Agence France-Presse. “He was a nice boy who posed no problem. They must have drugged him,” René’s wife Jeannine speculated of Hauchard’s ISIS overlords.

Hauchard’s uncle told BFMTV the Maxime he knew “wouldn’t hurt a fly.” The uncle told RTL radio Hauchard called his grandmother, ostensibly from Syria, on Nov. 2, for her birthday. In shock at news of her grandson’s video appearance, the grandmother reportedly was due to be hospitalized Monday night.

Hauchard converted to Islam in high school at 17, and is said to have suddenly begun wearing a beard and djellaba. He is thought to have self-radicalized online, calling himself Abou Abdallah al-Faransi (“The Frenchman”) on social networks.

In a July interview via Skype from Raqqa, the capital of the self-styled Islamic State, Hauchard told France’s BFMTV, “It’s funny because people think there is a sort of guru behind who puts things in people’s heads. In fact, no. I never met anyone. I would have liked to meet a brother.” He told the news channel he awaits death with joy and that martyrdom is the greatest reward.

French intelligence took note of Hauchard as early as 2011, before he made two trips between October 2012 and May 2013 to Mauritania for Quranic teaching, schooling he is thought to have eschewed as not radical enough for his liking. In August 2013, he bought a cheap ticket to Istanbul on the pretense of doing humanitarian work and crossed the border to Syria near Gaziantep, Turkey.

Boasting that he did little to hide his intentions, Hauchard told BFMTV, amused, about how airport security took little notice of his thick beard or military boots. Photos he would share on Facebook this year show Hauchard in Raqqa, wearing combat gear and wielding a variety of heavy weapons.

French investigators on Monday opened an investigation for murder in an organized gang with links to a terrorist enterprise targeting Hauchard and the other potential French suspect. The latest investigation adds to nearly 100 already on the books; 109 people have been indicted in the previous cases.

Just last week, the first convicted French Jihadist returnee was sentenced to seven years in prison. Flavien Moreau is a 28-year-old man originally from South Korea who was adopted by a French family when he was two. Interior Minister Bernard Cazeneuve said Monday that five potential attacks on French soil by jihadi returnees have been foiled in recent months and 138 people have been “neutralized,” an ominous term that was not fully explained.

Some 1,132 French nationals are said to be implicated in Jihadist networks at present, according to Paris Public Prosecutor François Molins. Of those, 376 are on the ground in Syria and Iraq, including 88 women and 10 minors.

“We have never in the history of counterterrorism been confronted with such numbers,” Molins told reporters on Monday.

As investigators continue to parse the latest ISIS video for foreign fighters among the headsmen, Hauchard stands as an alarming sign of ISIS’s reach in the West. Le Monde cites the estimated 23 percent of the 376 French jihadists in Syria that are thought to have had non-Muslim upbringings, like Hauchard. And as his stunned neighbors in Normandy might tell you, even allegedly nice guys are fair game.