KINSHASA, Congo (AP) — The lawyer for three Americans sentenced to death in Congo on charges of participating in a coup attempt filed an appeal Tuesday, he told The Associated Press.

A military court in Congo handed down death sentences last Friday to 37 people, including three young Americans, after convicting them on charges of participating in a coup attempt.

The defendants, most of them Congolese but also including a Briton, Belgian and Canadian, had five days to appeal the verdict on charges that include attempted coup, terrorism and criminal association. Fourteen people were acquitted in the trial.

Congo reinstated the death penalty earlier this year, lifting a more than two-decade-old moratorium, as authorities struggle to curb violence and militant attacks in the country. The men convicted in the coup attempt would likely be executed by firing squad.

Congo is a member of the Treaty of Rome, and because of that the reinstatement of the death penalty was illegal, according to Richard Bondo, the lawyer for the convicted Americans. The parliament should have decided on an alternative penalty, Bondo told the AP — but it hasn't so far.

Six people were killed during the botched coup attempt led by little-known opposition figure Christian Malanga in May that targeted the presidential palace and a close ally of President Felix Tshisekedi. Malanga was fatally shot while resisting arrest soon after live-streaming the attack on his social media, the Congolese army said.

Malanga’s 21-year-old son Marcel Malanga, who is a U.S. citizen, and two other Americans were convicted in the coup attempt. The other Americans are Tyler Thompson Jr., 21, who flew to Africa from Utah with the younger Malanga for what his family believed was a free vacation, and Benjamin Reuben Zalman-Polun, 36, who is reported to have known Christian Malanga through a gold mining company.

Marcel Malanga told the court that his father had forced him and his high school friend to take part in the attack.

“Dad had threatened to kill us if we did not follow his orders,” Marcel Malanga said.

Marcel’s mother, Brittney Sawyer, maintains that her son is innocent and was simply following his father, who considered himself president of a shadow government in exile.

In the months since her son’s arrest, Sawyer has focused her energy on fundraising to send him money for food, hygiene products and a bed. He has been sleeping on the floor of his cell at the Ndolo military prison and is suffering from a liver disease, she said.