Former Barcelona president Josep Maria Bartomeu was released from custody after spending a night in jail regarding irregularities during his administration.
Bartomeu was arrested on Monday, allegedly along with two other officials, after police raided Barcelona's headquarters over the controversial 'Barcagate' scandal.
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The club was accused of running a smear campaign against players and former players if they had criticised Bartomeu or others.
The club was not charged, but Bartomeu remained under investigation.
Bartomeu and former adviser at the football club Jaume Masferrer appeared before a judge and were provisionally released.
The former president and his lawyers will have access to the information gathered against them before they appear in court again.
Bartomeu's arrest comes just a week ahead of the club's presidential election.
Barcelona in turmoil
The legendary Spanish club has been in turmoil for two seasons after revelations Lionel Messi wanted to leave.
Coach Ronald Koeman discussed the turmoil and said every club faces tough periods, but this was not a good look.
"Every club has its difficult moments," Koeman said, who took over after the club's crisis erupted following the team's 8-2 loss to Bayern Munich in the Champions League.
"It's true that a lot has happened, but we remain motivated and will keep fighting to win titles."
Koeman, who was hired by Bartomeu said it was "obvious that this is not good for the image of the club".
Barcelona is coming off its first season without a trophy since 2007-08.
But the club is facing a swift exit from the Champions League after Paris Saint-Germain routed the Spaniard 4-1 in the first leg of the round of 16 tie.
Barcelona will also try and reverse a 2-0 first-leg loss to Sevilla in the Copa del Rey semifinals.
The club also sit five points behind Atletico Madrid in La Liga and level with rivals Real Madrid.
To make matters worse, Barcelona could also lose Lionel Messi after his contract ends this season.
Barcelona has been led by a caretaker board since the 58-year-old Bartomeu and his board resigned in October while facing a no-confidence vote.
He had been loudly criticised by Messi, whose request to leave the club last season was denied by the then-president.
The Spanish club has a debt of more than 1.1 billion euros ($A1.7 billion), in large part because of the coronavirus pandemic.
Members of the police's financial crimes department conducted the operation in five different locations on Monday, including Bartomeu's house.
Authorities said they were investigating "alleged crimes related to property and socio-economic order".
Barcelona had denied accusations that it hired - and overpaid - a company to make negative comments about its own players and opponents on social media to boost the image of senior club officials.
The company was accused of using fake social media accounts to discredit opposition figures, a list said to include Messi, Gerard Pique and former coach Pep Guardiola, when they expressed views that went against the club.
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