Video report by ITV News Washington Correspondent Robert Moore
Surveillance photos of the gunman in the Baton Rouge shooting have been released by officials, as the police said the attacker "intentionally targeted" police.
In a series of images from the scene taken as the incident unfolded, 29-year-old Gavin Long is seen outside a petrol station carrying a rifle.
Police also said they had recovered three guns that the former marine had purchased, and said he had scoped out areas where he could assassinate police.
Police said the weapons recovered were:
IWI Tavor SAR, 5.56 caliber rifle
Springfield XD 9, 9mm caliber pistol
Stag Arms M4 Variant, 5.56 caliber rifle
The images were shown on a screen at a press conference held by the Louisiana State Police, where officials detailed how the events on Sunday had unfolded.
Long killed three police officers and wounded three others, one of whom is still "fighting for his life" in hospital, police said.
A Baton Rouge SWAT team responded and killed Long, shooting him from 100 yards away, State Police Superintendent Colonel Mike Edmonson told the press conference.
Police said that "multiple pieces of evidence" had been recovered from the scene of the shooting, and that they were examining Long's social media footprint.