The Brazilian was paraded as a 57.1m euro (£47m) signing by Barcelona from Santos in June last year with the exact details of the contract not revealed due to a confidentiality agreement.
Following a complaint by a Barcelona club member, state prosecutors backed a legal challenge that called for a hearing to investigate a claim of "contractual simulation" or distorting the final figures over what was paid.
They pointed to 40 million euros (£32m) that was paid as part of the overall fee and went to a company owned by Neymar's father, which has led to extensive scrutiny of the deal and all those party to it - including the player's father.
And now Neymar, who is a prolific user of social media, took to Instagram to launch a robust and emotional defence of his father while also hitting out at those he deems "fake".
“I'm sorry, father, but this time, for the first time, I'm going to disobey you – I have to speak out,” he posted on Instagram.
“I wanted to thank you for the way you have overseen my career. It's thanks to you I played for the team in my heart, Santos FC, and I am now at my dream team, FC Barcelona.
“I know a lot of people are coming out with a load of rubbish about us, questioning our character. I've also discovered that we have a huge amount of fake friends."
Neymar pays no reference to the specifics of those fake friends but makes an emotional plea to his father to join him in Spain.
“When Thiago Silva said he would die on the pitch for me, I thought the same about him. But for you I would not just die, I would give the life of my only son!
“So I'm asking you to come back to Spain, I miss you. I'm playing again in a few days and I need you here.
“It's only a matter of time before people realise that you did nothing wrong. You were just being my father through and through. I love you and we are in this together.”
Read the original article on Football Espana - The ultimate website for English-speaking fans of Spanish football