Former Barcelona president Josep Maria Bartomeu, detained Monday as part of a probe into last year's 'Barcagate' scandal, will appear before a judge on Tuesday, a police source said.

His right-hand man Jaume Masferrer will also appear before the investigating judge leading the probe after spending the night at a police station along with Bartomeu, the sourced added.

Two other men who were also detained as part of the operation which involved a search of Barcelona's stadium -- the club's current chief executive Oscar Grau and its head of legal services Roma Gomez Ponti -- were released late on Monday.

The so-called 'Barcagate' scandal involves allegations that the club covered up payments made to a company called I3 Ventures, hired to boost the image of then-president Bartomeu on social media.

Part of the social media campaign included criticising current and former players, like Lionel Messi, Pep Guardiola and Xavi Hernandez. Messi described the controversy as "strange" in an interview with Catalan newspaper Mundo Deportivo.

Spanish radio station Cadena Ser, which broke the story, claimed Barca paid I3 Ventures an inflated fee and put payments through in smaller, separate amounts to avoid the club's financial controls.

Bartomeu maintained the company had been hired only to monitor posts on social media and announced an internal audit by PricewaterhouseCoopers, which cleared the club of financial corruption in July.

He resigned in October, avoiding a vote of no confidence triggered after more than 20,000 club members signed a petition against him.

His departure came in the same month Barcelona announced losses of 97 million euros ($114 million) for last season and following a dramatic decline in performances on the pitch as well as a personal falling-out with Messi.

His successor is due to be elected on Sunday, when club members will choose between the final three candidates, Joan Laporta, Toni Freixa and Victor Font.