The suspect in the New Orleans attack that killed 14 people on New Year’s Day is believed to have acted alone in a “premeditated and evil act,” the FBI has said.
The latest information is counter to that provided by the law enforcement agency earlier in the investigation, when it said it believed that multiple people were involved.
Shamsud-Din Jabbar, a 42-year-old US citizen, is now the sole suspect. He is believed to have driven a pick-up truck into a crowd on a busy New Orleans street, before exiting the vehicle and firing a weapon. He was shot dead by police at the scene.
The FBI says an Islamic State (IS) group flag was found inside the vehicle he was driving.
Two improvised explosive devices (IEDs) were also found nearby, police said.
Surveillance footage viewed by police shows Jabbar placing each of those devices in coolers along the busy Bourbon Street in New Orleans, said Christopher Raia, the deputy assistant director of the FBI’s counterterrorism division.
Speaking to reporters on Thursday, Mr Raia clarified that based on the latest available evidence, Jabbar is believed to have acted alone.
He added that the investigation remains ongoing with officers chasing leads across the country.
“We have received just over 400 tips from the public,” he said, from people both in the state of Louisiana and elsewhere in the US. Officers are also reviewing hundreds of hours of surveillance footage, Mr Raia said.
A clearer timeline of the events leading up to the attack has since emerged, officials said.
Police believe that Jabbar rented a Ford F-150 pick-up truck in Houston, Texas on 30 December and drove it to New Orleans, Louisiana on the evening of 31 December.
That evening, Jabbar posted several videos on social media where he proclaimed his support for the Islamic State group, Mr Raia said.
There were five videos in total, timestamped from 01:29 to 03:02 local time.
Mr Raia said that in one of the videos, Jabbar stated that he originally intended to harm his family and friends, but was concerned that news headlines would not focus on the “war between the believers and disbelievers.”
Jabbar also stated that he joined IS before the summer, Mr Raia said.
Louisiana Attorney General Liz Murrill told US media earlier that a fire broke out in a New Orleans Airbnb believed to have been rented by Jabbar on Wednesday morning – and that explosive devices associated with the attack are suspected by investigators to have been made in the Airbnb.