Chagaev is under investigation after media reports suggested he had submitted a falsified document to prove his solvency during a bankruptcy trial.
The football boss, accompanied by his lawyer, Jacques Barillon, attended a hearing at the public prosecutors office on Thursday afternoon.
A prosecutor in the canton of Neuchatel said last week that a Bank of America document provided by Chagaev stating that he held $35 million was not produced by the institution.
Over the past fortnight, the Swiss courts have searched the Geneva offices of two of Chagaev's companies, his home in Saint-Sulpice near Lausanne and the office of Neuchatel Xamax.
Chagaev's ownership of Xamax has been controversial in Switzerland -- earlier this season he sacked the entire coaching staff after the side lost 2-0 to Basel.
More recently, the Swiss Football League fined the club 20,000 francs (€16,440) for flouting licensing rules, after they failed to respond to queries over their budget.