The former Tottenham midfielder was a key witness in ex-Dinamo Zagreb chief executive Zdravko Mamic’s trial in Osijek.
Modric gave evidence last week at the corruption trial last week – with Mamic accused of evading £1.4m in taxes and embezzling £10.5m of the club’s money along with his brother Zoran, club director Damir Vrbanovic and a tax administration employee Milan Pernar.
Another strand of the case revolved around Mamic illegally keeping a chunk of the £16.5m Spurs paid Dynamo to sign Modric in 2008 – with the Croatia international called in to reveal what happened.
An investigation showed he did keep the money, with the defence not disputing the withholding of cash.
The disagreement is over a 50 per cent agreement between Dynamo and Modric – which the prosecution claim was backdated after Modric had already left.
Modric originally admitted this was the case before changing his statement, claiming he was confused.
“When speaking about that, I was talking about a personal contract between Mamic and me, which regulated the split of the transfer fee,” he said.
But now the Croatia State Attorney Office has started an investigation into Modric’s evidence, with worries he lied to the court.
If found guilty of perjury, Modric could face between six months and five years in prison.
In a statement, the State Attorney’s Office said: “State Attorney’s Office in Osijek opened the investigation against Croatian citizen (1985) due to the existence of reasonable doubt that when giving testimony before the County Court in Osijek committed a crime against justice by giving false testimony under Article 305, paragraph 1 of the Criminal Code / 11. (6th 19th 2017).
“There is a reasonable doubt that on 13 June 2017 at the Osijek County Court, during a hearing in a criminal case against the first accused Croatian citizen (1970) and others, for the criminal offence of abuse of position and authority in Article 291, paragraphs 1 and 2 of the CC / 11; although he was warned that a witness is obliged to tell the truth and that is giving a false statement offence; examined as a witness falsely testified that the annex to the agreement.”