Authorities have arrested two teenagers in connection with the “execution-style” double murder of Metairie father and son David and Nicholas Pence following a “random” armed robbery that appeared to go horribly wrong, Jefferson Parish Sheriff Newell Normand said Sunday.

The killings happened just before midnight Wednesday in the 3700 block of Clifford Drive, sending fear through a normally serene neighborhood and shocking neighbors close to the gregarious family man and his popular son.

Nicholas Pence had just finished celebrating a flag football game victory with friends in a side garage dubbed “the Mancave,” authorities and neighbor Michael Soignet said. Just moments later, after the 25-year-old’s friends had left, he and his father would be dead.

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Normand said officials believe the arrested suspects, Haraquon Degruy, 18, and Dexter Allen, 17, attempted the armed robbery after previously canvassing the neighborhood to burglarize cars. He said evidence suggests that Allen pulled the trigger after coming in through an open side door of the Pences’ home just after the party ended, in what neighbors said was normally a quiet and safe area.

The incident escalated, and, for unknown reasons, Allen shot the father and son, Normand said.

The Jefferson Parish Sheriff’s Office said David Pence was found sitting in his chair, with gunshot wounds to the neck, chest and leg. His son was found on the floor with gunshots to his face and side of his head. Both were pronounced dead at the scene.

“Once again, this particular happenstance was completely, totally, shock-the-conscience type of homicide — obviously execution-style, very close,” Normand said during a news conference Sunday. “I guess the most obvious question is, ‘OK, we got the car burglary, why this?’ ”

The victims’ wife and mother, Elizabeth Pence, dialed 911 to report that her family members had been shot and appeared to be dead. She had been asleep in her bedroom when she heard what sounded like glass breaking and possibly the sound of gunshots, she told investigators.

At that time, she also noticed that her purse, which included items such as an iPad and iPhone, was missing from the kitchen counter. Authorities didn’t say if there was screaming or any other acknowledgment of a home invasion.

“We’re not sure if Mr. (David) Pence was even awake at the time,” Normand said. “There’s evidence at the scene to suggest possibly that he was not.”

Authorities also saw that the father’s black Mustang, parked in the driveway, had been rifled through. The door was ajar and the glove compartment was open, and four shotgun shells were found on the ground.

Authorities said one of Nicholas Pence’s friends who was at the football victory party said he remembered seeing a white Toyota Highlander and its occupants “acting suspiciously” as they moved through the block with the headlights off. He left Pence’s house a short time later, the friend said — just a “short time” before Elizabeth Pence discovered that her husband and son had been shot, authorities said.

“They were riding around, and what we believe happened is there’s a garage area in the back and the lights were on,” Normand said of Degruy and Allen. “There’s a bunch of stuff you can see from the street in the garage. The information that we have is that he grabbed the shotgun out of the car ... and intended to go down the driveway and commit an armed robbery, we believe.”

At that point, Normand added, “all of the folks had left” the party, but the side door to the house had been left wide open, and that’s how Allen gained entry to the house.

That detail didn’t surprise at least one neighbor. According to Soignet, the neighborhood was considered so safe that the Pences often left the side door open so that friends could come into the house and grab a beer during parties in the “Mancave” garage.

After canvassing the neighborhood, authorities were able to find security video from neighbors that would lead to the arrest of the two teens now in custody.

The whole incident began, it seemed, with a series of car burglaries.

Video surveillance showed a man pulling on door handles of vehicles around Clifford Drive and 9th Street, near where a vehicle burglary had just happened. Surveillance also showed an SUV that “appeared to be connected” with the man, according to the JPSO.

Authorities would learn later that several other vehicles had been burglarized, and a fingerprint lifted from one of those cars would connect Degruy to the area.

“They were in the area to commit vehicle burglaries. That’s what drew them to that area,” Normand said.

An arrest warrant was obtained for Degruy on a burglary count on Thursday, the same day that officials learned the white Toyota Highlander seen in the surveillance video had been stolen in an armed robbery in New Orleans East.

“So within a short period of time after this occurring, we had a vehicle and we had an identity of a female,” Normand said. “We did not know whether or not they were linked to the murder, but we knew they were in the area around the same time as when the murder occurred.”

The following morning, U.S. Marshals Task Force members were helping the JPSO search for Degruy when they found the white Highlander parked in New Orleans East near an apartment complex, officials said. Shortly thereafter, they saw Allen and Degruy enter the car, with Allen driving.

When Task Force members tried to stop the car, Allen led them on a chase that ended when the vehicle crashed near Downman Road and Interstate 10. Allen tried to flee, jumping off a bridge while Degruy was taken into custody, but he was apprehended without incident after a brief chase.

“We tried to take the vehicle down, and we ended up in a chase with them,” Normand said, describing a scene that could have been taken from an action movie. “All the while during the chase they were throwing evidence out of the vehicle that linked them not only to the murder but to other vehicle burglaries possibly in the area.”

Normand said Degruy admitted to being in the Metairie neighborhood with Allen at the time of the murders. He said Degruy told officers that she and Allen were committing auto burglaries in the area. He said she ultimately admitted to having knowledge of the killings.

Degruy said Allen at one point returned to the Highlander, retrieved a shotgun from it and told her to wait there for him, Normand said. When Allen came back, Normand said, he had with him an iPad and a cellphone — and at that point he told Degruy about the shooting.

“He ultimately comes back to the car and tells her, ‘I just shot and killed somebody. We gotta get out of here,’ ” Normand recounted.

After the killings, the pair went to Allen’s mother’s house, in the 2200 block of Arts Street, where authorities would later find additional seized items “commonly taken in auto burglaries,” Normand said.

A shotgun recovered from under that house is believed to be the same one used in the murders, based on ballistics tests and the shell casings recovered at the scene, authorities said.

When detectives interviewed Allen on Saturday, he admitted to being with Degruy and to the car burglaries but denied any involvement in the murders of David and Nicholas Pence, according to the JPSO.

Normand said authorities from Jefferson and Orleans parishes teamed together to solve the murder mystery.

“We dedicated a lot of assets and resources to this because we definitely wanted to bring this to a conclusion quickly,” Normand said, adding that some officers worked on the case for as many as 40 hours without sleep. “So we could attempt to bring some sense of calm to this neighborhood in this random murder.”

Degruy was booked into Jefferson Parish Correctional Center on two counts of being an accessory after the fact to first-degree murder and one count of vehicle burglary.

Allen was in Orleans Parish Prison as of Sunday, being held on counts resulting from his flight from Task Force members. Jefferson Parish has placed a hold on him for two counts of first-degree murder.

Neither teenager had any “significant” prior criminal history, Normand said. And while officials managed to place the pair at the scene and connect the evidence, he said, he still couldn’t understand what caused Allen to go into the house and pull the trigger.

“We’ve done everything we can do on our part to try and bring this to a successful conclusion,” Normand said. “However, after all the work that’s been done, we still don’t really have the answer as to why.”