Among the injuries, gunshot wounds can be seen, as well as signs that blindfolds and handcuffs were used, the doctor states.
Almost all of them had their eyes bound and had been tied up and they had been shot between the eyes, says Ahmed al-Farra, head of Nasser Hospital's pediatric department, to The Guardian.
There were also scars and discolored skin patches showing that they had been beaten before they were killed. There were also signs that their bodies had been abused after they were killed.
According to Ahmed al-Farra, the remains have not been able to be identified, as the hospitals in Gaza do not have the ability to perform DNA analysis.
The returned bodies are part of the ceasefire agreement in Gaza, in which it is stated that Israel and Hamas will exchange hostages and prisoners as well as people who were killed during the battles. The exchange has taken place with the help of the International Committee of the Red Cross (ICRC).
The Guardian has sought representatives of the Israeli military for a comment. They refer the question to the prison authority, which has not responded.