The Syrian, who arrived by boat in early October, has not been seen at the Lampedusa immigration centre since Sunday morning, Corriere della Sera said.
His footage led to the centre’s management staff being sacked, a national investigation launched and the EU to warn Italy of the way it treats migrants.
After the film was shown by state broadcaster Rai earlier this month, the Syrian lawyer was subjected to threats and intimidation. At one point he was moved to the police office within the centre to protect him from a mob waiting outside, Corriere said.
Police have unsuccessfully searched the island and have since moved northwards to Sicily, in case he stowed away on a ferry to the larger island.
Just days before the disappearance, more than half of the 200 migrants at the centre were flown off Lampedusa to the Italian mainland.
The move came a day after Prime Minister Enrico Letta pledged to reform Italy’s immigration laws and revamp the asylum system in the new year.
According to government estimates the number of migrants arriving in Italy has tripled in a year, to 42,000 in 2013.