While he has not been officially named by police, the suspect has been widely reported to be Kenneth Darlington, 77, a retired American lawyer and university professor who lives in Panama.
Police said on X (formerly Twitter) that a man has been arrested at the scene, where he was charged with aggravated homicide and illegal possession of a firearm.
Mr Darlington, who was born in Panama but has US citizenship, was caught up in a traffic jam on Tuesday on a highway 55 miles west of Panama City, caused by protesters campaigning against the recent deal the Panama government made to restart a copper mine.
The protest attracted a group of photographers and TV reporters to the site of the traffic block, where they had lined the middle of the highway with tyres, flags, tree branches and stones to stop the cars.
Despite the cameras, horrific video footage showed Mr Darlington, who was allegedly caught in the traffic, walking up to the protesters and open firing, leaving two men dead.
According to the Panama TV network TVN, who reported they were able to access the court hearing on the shooting incident for a few minutes, the suspect uttered something along the lines of “this ends here” before leaving his vehicle and storming up the highway towards the protesters.
The widely circulated video footage shows Mr Darlington arguing with a group of men from the protest.
He allegedly asked who the leaders of the campaigners were, to which the men replied that there were none.
“I don’t want to talk to women. I want to talk to men,” he responded, according to TVN.
While he was still confronting the protesters, he took out a handgun from his pocket and kept it in his hand as he started to tear away the blockades on the road, the outlet said.
One of the protesters could be heard saying: “Why don’t you shoot?” while others shouted, “Are you going to kill someone?”
According to the outlet, Mr Darlington replied: “Do you want to be the first?”
After arguing with the group, the suspect then reportedly opened fire, hitting one man in a black t-shirt carrying a flag, who immediately fell to the ground.
Again, Mr Darlington allegedly opened fire, according to video footage captured at the scene, which hit another man, also in a black t-shirt.
The victim could be seen holding his shoulder in immense pain and staggering to the side of the road, where he collapsed, according to reports.
The men shot were identified as two teachers, Abdiel Díaz, who died at the scene, and Iván Rodríguez, 62, who was taken to the Juan Vega Méndez clinic but was pronounced dead on arrival, according to local outlets Agence France-Presse and Newsroom Panama.
TVN reported that Mr Darlington proceeded to move blocks out of the way with his gun still placed firmly in his hand, then returned to his car.
When he approached his vehicle, another person in a car asked him, “Are you aware of what has happened?” to which he replied, “Yes, I killed one and shot another.”
He then got back into his car, turned to a woman, reported to be his girlfriend, and said, “Let’s go.”
The woman allegedly replied, “We are not leaving”, before calling up the National Police Agents, according to TVN.
The police later stopped the car, seized Mr Darlington’s handgun, then handcuffed the suspect and took him into their police vehicle.
TVN said the suspect appeared in a two-hour court hearing the next day.
The effects of the protests, which started over three weeks ago, have had a ripple effect on the whole of Panama.
Construction worker unions and teacher unions have banded together to protest restarting a copper mine, that was agreed to by the Panama government and a Canadian firm on 20 October, which will be dug in the jungle west of Panama City.
The protests have also rolled into a wider discontent with the Panamanian government, Reuters said.
The roadblocks set up by protesters have caused up to $80m in daily losses to businesses, according to Panama’s association of company executives and schools were forced to close for over a week, reported Reuters.
Thousands of medical appointments have also been reported to have been missed since the protests began.
Officials have urged the protesters to stand down, reiterating that the mine is expected to generate $375m annually in revenue.