Filippo di Pierro, the boss of Spanish third division side Eldense, was arrested after his side's 12-0 defeat by Barcelona's B team on Saturday.
Di Pierro, who joined the club in January, was hired by an unnamed Italian investment group that has since severed ties with the club.The defeat sealed Eldense's relegation.
Eldense player Cheikh Saad was the first to point the finger at a number of his teammates and coach.
Saad told radio station Cadena Copa that certain players stood to make “huge sums” of money from bets placed on the match. The club’s president David Aguilar then reported his suspicions to the police and the Spanish football authorities.
In an interview with Spanish radio station, Cadena Ser, Eldense defender Emmanuel Mendy said the club's assistant coach, Fran Ruiz, had spoken to him about a plan to fix the game.
"He asked me if I was in and how much I wanted and if I wasn't in then I wouldn't play," said Mendy.
Barcelona first-team coach Luis Enrique has also commented on the situation, which he described as "very delicate".
"It's exclusively related to Eldense,Barca B have nothing to do with it and is another victim of this racketeering.I'm glad that it's being investigated and is being taken seriously."