A banner reading 'Madrid hates Real' and an inflatable black effigy dressed with a replica of Vinicius' No. 20 shirt appeared hanging on a bridge near the club's training ground before a match against rival Atletico Madrid on January 26th.
The prosecutor accused four members of far-right radical group Frente Atletico, who are followers of Atletico Madrid, of making threats against Vinicius and also of infringing fundamental rights, a prosecutors' office statement said.
The four showed "an unequivocal sign of contempt and repudiation of the victim's skin colour and an attempt to undermine the victim's peace of mind", it said.
The prosecutor also requested joint compensation of 6,000 euros in civil liability for the moral damage caused to the soccer player.
The four men, who declined to testify when they were arrested in May, were released on bail after a court banned them from getting near Vinicius or communicating with him. They were also barred from Real's stadium and training ground as well as Atletico's playing venue.
Vinicius Jr was in the spotlight in Spain earlier this year after calling Spain's LaLiga soccer league and the country itself racist following verbal abuse from fans he suffered during another Real match in Valencia in May.
That game was halted for 10 minutes as the Brazilian forward pointed out fans yelling invective at him. He was then involved in an altercation with some Valencia players which led to him being sent off in the second half.
The sporting world has shown solidarity with him since then and the Brazilian government called for severe sanctions against those responsible for the racial slurs.
In October, Vinicius testified as a witness in a court investigation against three fans for allegedly making racist gestures towards him during the match in Valencia. He was also called to testify in a similar case over insults in the Mallorca stadium in February.