Tono was one of seven people arrested on Friday and Spanish media reported they are being held on suspicion of extortion and threats.
Tono's lawyer Emilio Perez Mora said he could not comment on the nature of the allegations because the case was subject to "legal secrecy" and added that he did not know why the player had been accused.
"It's unfortunate and a tremendous injustice that he is imprisoned in Teruel jail," Perez Mora told Cadena SER radio.
"He's there because the judge believes there is a considerable flight risk and that he has not cooperated with the administration of justice, and because he believes there is the chance he may commit another crime.
"He is absolutely (innocent). Tono has nothing to do with the type of crimes that have been quoted.
"I will not get into the matter because the case is subject to legal secrecy and at this point we do not know why Tono has been accused."
Local police have not yet responded to a Reuters request to confirm the reason for the arrest.
Left back Tono, 29, signed a new contract with Levante until 2023 on Wednesday and has scored one goal in 17 La Liga games this season.
"As judicial proceedings are subject to secrecy, the club, without any prejudice, will show our support to the player and his family," Levante said in a statement late on Friday.
"We do not know the circumstances that led the investigating judge to take this action. The player deserves respect in this difficult moment and is presumed innocent until found guilty.
"The club will not make any further statements until there is more news about the cause of his arrest."
(Reporting by Rik Sharma; Editing by Toby Davis)
