A prosecutor who began re-examining the case in 2010 has taken testimony from Pino Pelosi, the man convicted of the murder, in which he says two other men beat the director to death, contrary to his earlier claim to have acted alone.
DNA samples from the clothes Pasolini was wearing on the night have meanwhile revealed traces belonging to at least three people, according to press reports on Tuesday.
Many Italians have long believed that Pasolini was murdered by a group of neo-fascists, either because of his radical views and his homosexuality, or because his creative work was seen as a threat by the Christian Democrat-dominated establishment.
Pelosi was a 17-year-old prostitute at the time of the November 2nd 1975 killing.
He said at his trial he had killed Pasolini at the seaside resort of Ostia near Rome after the director had tried to rape him. He was given a nine-year prison sentence but his version of events was always regarded with scepticism.
As he was much smaller than Pasolini, many questioned how he could have overpowered him and inflicted such a savage beating. The director was left with multiple broken bones and crushed testicles and his body was partly burnt.
In his new testimony, Pelosi reportedly says that he and Pasolini had just got out of the director's Alfa Romeo car when they were attacked by at least six other people who had arrived in two cars and on a moped.
Two of the attackers laid about the director with bars before running him over in a car similar to his own one, Pelosi says.