A Spanish court Wednesday launched a fraud investigation against Barcelona striker Neymar, a judicial source said, dragging the Brazilian star into a case in which the club's president faces trial.

The National Court admitted a lawsuit alleging "corruption and swindling" by the star player, his father and his former club Santos linked to the signing of Neymar by Barca in 2013, the source told AFP.

The case has been brought by a Brazilian investment fund, DIS, which owned part of the transfer rights for the player, the source said.

The 23-year-old helped Barcelona to a stunning triple of Spanish league, cup and Champions League titles this season.

He was to captain Brazil on Wednesday against Colombia in the Copa America tournament in Chile.

DIS received 6.8 million euros ($7.7 million) out of the total 17.1 million that Barca paid to Santos, but claims it may also be due a share of the overall transfer payments.

Santos has also launched an action in Brazil against Barcelona and the player and his father over alleged irregularities in the deal.

In a separate lawsuit, a judge last month ordered Barcelona's president Josep Bartomeu, his predecessor Sandro Rosell and the club itself to stand trial over alleged tax fraud linked to the signing.

They have always said they paid a transfer fee of 57 million euros to sign the Brazilian star from Santos in 2013.

The courts suspect the actual price was at least 83.3 million euros and that Rosell and Bartomeu hid the real cost from the taxman.

The case was shifted from Madrid to a court in Barcelona last month after an appeal was upheld. No date for a trial has been set so far.

It is alleged the overall fee was split between a number of different contracts between Barcelona, Santos and Neymar himself.

In doing so, Barcelona stand accused of defrauding the Spanish taxman of 12.7 million euros.

Prosecutors are seeking a prison sentence of two years and three months for Bartomeu and seven years for Rosell, as well as a 22.2 million euro fine for the club.

Bartomeu's involvement could seriously damage his campaign to be elected as president in club elections on July 18.