Shortly after the fire Qatar police held four Villaggio mall management officials and Iman Al Kuwari, the Qatari owner of Gympanzee, for questioning.
Villaggio has been closed since the fire.
An initial report, completed in June, found negligence by many parties led to the blaze.
It concluded there was negligence by the security team overseeing the complex in responding to the fire.
It also found there was no plan in place to deal with an emergency of that scale and staff not been trained to cope with a fire, Aljazeera reported.
The committee investigating the fire found the childcare centre was not licensed by Qatar's Ministry of Social Affairs, as required by law, meaning it did not have the safety measures required for a nursery.
It said the fire started at the upper floor of a Nike sports store after faulty electrical wiring in a fluorescent light caused a spotlight to catch fire, before rapidly spreading to the adjacent nursery.
While civil defence workers arrived within three minutes of being alerted to the fire, it took them another 30 minutes to learn that children were trapped in the nursery.
The committee made 11 recommendations to prevent or reduce the risk of a repeat fire.