Footage shows Mr Thompson and Marcel being forced to their feet by soldiers who tie their hands behind their backs.
Friends said Marcel had pitched the trip to many of his high school friends in the months leading up to the failed coup attempt. Teammates said he had become increasingly desperate as friend after friend declined.
Luke Barbee, another former teammate who lived with Marcel last year, said: “He did call me to ask if I wanted to go to Africa for vacation, as well as a few of my other friends, but he did not offer to take more than a single one of us at a time.
“He only asked so many of us because he kept getting denied until Tyler said yes to the trip.”
Jaden Lalor, another teammate who had been asked, said Marcel had a strained relationship with his father and could have been pressured or manipulated into following his plans.
Mr Lalor said: “Marcel is a super respectful kid, rough around the edges, but not enough to go and murder people.
“I know they had to have been brainwashed or forced to do this because Tyler had never been one for conflict. He’s one of the most laid back or chill kids you would meet.”
A British national is also among those held, according to authorities, who released a film of a man called Ezangi Viatochir Youssouf who says he is from England.
Maj Gen Sylvain Ekenge, an army spokesman, said the suspects were being held by military investigators.
He told the Telegraph: “They are all considered as state enemies, captured enemies of the nation. They will be treated like that.”