scene of New Orleans attack
scene of New Orleans attackUSA TODAY NETWORK via Reuters Connect

Shamsud-Din Jabbar, the terrorist who murdered 14 people in a ramming attack in New Orleans on New Year's Day last week, used a “very rare explosive compound” that had never been used in a terrorist attack in the US or Europe, police said.

Jabbar, who had an ISIS flag in his vehicle, had placed two improvised explosive devices in the area that he was unable to detonate before he was killed in a shootout with police. Two senior law enforcement officials told NBC News that the compound used in the IEDs was R-Salt, a compound that is similar in many ways to RDX.

Officials are investigating how Jabbar learned to manufacture the compound. An explosives-making workshop was found in Jabbar's trailer home in Texas.

Jabbar had visited New Orleans twice in the months preceding the attack, using Meta smart glasses to record footage of the area and plan his assault, CNN reported Sunday, citing FBI New Orleans Special Agent in Charge Lyonel Myrthil. He stayed in a rental property in New Orleans for a few days starting October 30, during which he used a bicycle to traverse the French Quarter and capture video, Myrthil said. He made a second visit on November 10, with investigators still piecing together the details of that trip.

Jabbar wore the Meta smart glasses during the attack on New Year’s Day but did not activate them at the time. The glasses were recovered after his death.

Details of Jabbar’s planning were disclosed during a Sunday press conference, where authorities outlined a timeline of his actions and shared videos documenting his movements leading up to the attack.

The 42-year-old Army veteran, who had pledged allegiance to the Islamic State (ISIS), drove a rented pickup truck into a crowd of revelers on Bourbon Street shortly after 3:00 a.m., before opening fire. The assault left 14 dead and at least 35 injured, the FBI reported. The rampage ended when Jabbar’s vehicle collided with a cherry picker forklift, and he was fatally shot by police.

The attack has raised concerns about security measures on Bourbon Street and how a large truck was able to access one of the nation’s busiest pedestrian zones.

According to the FBI, Jabbar entered Louisiana around 2:30 p.m. on December 31 and checked into an Airbnb with his rented Ford F150 truck at approximately 10:00 p.m. Hours later, just after midnight, he set the rental home on fire and drove away in the truck, said Joshua Jackson, the special agent in charge of the New Orleans field division of the Bureau of Alcohol, Tobacco, Firearms and Explosives.

“We believe he intended to burn the house down to destroy evidence of his crimes,” Jackson said, adding that the fire may have also been meant to divert emergency responders. However, the blaze was contained, and firefighters extinguished it by 5 a.m.

After leaving the property, Jabbar placed two improvised explosive devices (IEDs) on Bourbon Street, using a rolling cooler and a bucket cooler to conceal them. A transmitter to detonate the IEDs was discovered in his truck, and bomb-making materials were found at the Airbnb and his Houston residence, Myrthil stated.

One IED, in a rolling cooler, was placed at Bourbon and St. Peter Street at 1:53 a.m., but a passerby, who authorities say was not connected to the attack, moved the cooler a block away. The second device, hidden in a bucket cooler, was left at Bourbon and Toulouse Street at 2:20 a.m.