Four Wilson Security guards at Australia's asylum seeker detention centre on Nauru reportedly used a cable tie to handcuff an eight-year-old boy as a joke.
The Guardian reports that the 2013 incident report contradicts the testimony of Wilson Security bosses, who told a Senate inquiry last week that the use of restraints was very rare.
The report says a Save the Children worker noticed four Wilson officers tying the boy's hands together in 2013, and was told by the smiling officers that it was a joke and "maybe now he'll stop fighting" before he was released.
Save the Children had identified the child as vulnerable because of a history of trauma in his home country and significant developmental issues that had manifested as behavioural problems.
The Guardian reports the boy was also later the victim of a reported sexual assault while in detention on Nauru.