The Real star has been summoned to testify on July 31.
Ronaldo, 32, has denied the charges and is threatening to leave Spain after running into problems with tax authorities.
However, Perez said that he had not spoken to Ronaldo, who is on duty for Portugal at the Confederations Cup in Russian Federation, which ends on July 2.
The two also clashed during their time together at Real Madrid, making matters even more complicated.
However, Mourinho's representatives Gestifute Media issued a statement on Tuesday evening saying their client had "not received any notification" of the actions by the authorities in Spain, as well as circulating a copy of an official tax document dated July 3, 2015 which covered the periods in question.
Ronaldo was accused last week by a state prosecutor of four counts of tax fraud totalling €14.7 million. "It is possible that the Spanish tax authorities will announce further investigations into other individuals before the end of this month", says the paper.
The agency published copies of the certificates.
Angel Di Maria will pay a fine of £1.76 million to avoid spending time in prison after admitting to tax fraud.
The prosecutor said last Tuesday that there was evidence that Ronaldo used a shell company in the Virgin Islands to hide the money he had made from image rights.
The Portugal global had knowingly used a "business structure" created in 2010 to hide his income in Spain from his image rights.
Ronaldo's trouble coincided with the same Madrid-based prosecutor's office accusing Mourinho of two counts of tax fraud.
Real Madrid's Portuguese forward Cristiano Ronaldo celebrates his second goal during the UEFA Champions League semifinal first leg football match Real Madrid CF vs Club Atletico de Madrid at the Santiago Bernabeu stadium in Madrid, on May 2, 2017.