Travis Boys, the accused killer of New Orleans Police Department Officer Daryle Holloway, pleaded not guilty Monday morning to a first-degree murder charge in the June 20 fatal shooting inside the officer’s patrol vehicle.

Boys, 33, once again appeared in court under heavy security, wearing a bulletproof vest as Orleans Parish Criminal District Court Judge Karen Herman accepted his plea.

A grand jury indicted Boys within five days of Holloway’s slaying, which happened as the officer was transporting Boys to jail after his arrest on suspicion of shooting at his wife. Holloway was not the arresting officer, but he had offered to help his colleagues in the 5th District.

District Attorney Leon Cannizzaro’s office plans to seek the death penalty against Boys, who had a history of escaping from law enforcement prior to the time he is accused of firing a shot from a .40-caliber handgun into Holloway’s chest, court records show.

Police have not said how they think Boys managed to get hold of the weapon he allegedly used to shoot Holloway before fleeing at North Claiborne and Elysian Fields avenues on the morning of June 20, or whether other officers had failed to properly search the suspect.

Boys is being held without bail.

His public defenders, Christopher Murrel and Anna Van Cleave, are seeking to ensure that DNA material and other evidence that police gathered from the bloody police SUV, including any video, remain intact.

Police have said Holloway’s body-worn camera was working and recorded a struggle as the dying officer tried to keep Boys in the vehicle.

Police have said Boys yelled three times, “Let me go before you kill yourself!” after he had maneuvered his way through a port into the front seat.

Herman set the next court date for Boys for Aug. 20, the deadline for prosecutors to turn over evidence to Boys’ attorneys.

Follow John Simerman on Twitter, @johnsimerman.