Cassano's career has been pockmarked by controversy with the Bari-born forward having regularly clashed with coaches and club presidents, while at Euro 2012 he argued he would prefer no gay players to be in Italy's squad.
According to the director of the Portobello Safari Resort in Mangaratiba, Italy's base just outside Rio de Janeiro, Cassano maintained his reputation for crazy outbursts at the World Cup in Brazil.
"Cassano was out of control," he told Sport Mediaset.
"The cleaning lady went up there to clean the room, which is necessary, and he shouted in her face.
"He's not normal in the head."
Cassano came off the bench in Italy's two defeats in Brazil.
The owner of the resort also cast doubt on the team spirit within Cesare Prandelli's squad, with Italy having been eliminated in the group stages of the World Cup after defeats to Costa Rica and Uruguay.
"Everyone in the staff agreed there was a lack of World Cup spirit," he said.
"Maybe it would've been different without the families, as they could've been in a different hotel.
"I saw (Mario) Balotelli and Cassano detached from the rest of the squad. It was obvious. Gianluigi Buffon, Andrea Pirlo and Daniele De Rossi were very likeable and nice with us. Buffon was the nicest.
"There was all the calm in the world here but without that unity you aren't going to win a World Cup."
