NEW ORLEANS — The Texas man who sped along Bourbon Street and ran down New Year's Eve revelers, killing 14, had visited Egypt for about a month in 2023, his half-brother told ABC News.

Federal investigators are looking into Shamsud-Din Jabbar's travel as it seeks a motive for Wednesday's attack. The FBI has said it is looking into the case as a possible act of terrorism, and wants to know whether Jabbar was radicalized before traveling abroad or if the travel marked the start of his radicalization.

Abdur Jabbar, 24, told ABC News that his half-brother went to Egypt alone, telling relatives he was going “because it was cheap and beautiful.” Abdur Jabbar said his half-brother returned with souvenirs that included three rings, tea and a wooden box.

Investigators want to know what Shamsud-Din Jabbar did in Egypt, why he went and who he interacted with.

“This next most important phase of the investigation is to find out how that radicalization happened and if it happened on that trip. That’ s priority No. 1,” Orleans Parish DA Jason Williams told ABC News.

Since the attack early Wednesday, officials spent the first day ensuring there weren't other suspects. Since Thursday, investigators have been focused on piecing together his path to radicalization and the events that led up to his decision to attack the Bourbon Street.

“The picture is getting less pixelated,” one investigator told ABC News, "but it’s slow going.”