San Lorenzo goalkeeper Pablo Migliore was arrested on the pitch on Sunday accused with perverting the course of justice in the case of a football hooligan who is wanted for murder.
Migliore, 31, is suspected of helping Boca Juniors barra brava (hooligan) member Maximiliano Mazzaro escape, a man who is wanted for beating his neighbour Ernesto Cirino to death in 2011. The San Lorenzo captain played for Boca between 2006 and 2008.
He was arrested after San Lorenzo had lost 1-0 at home to Newell's Old Boys. Police sealed off the Nuevo Gasometro stadium and arrested the player while he was still in full kit on the pitch, since which time he has been in jail.
San Lorenzo president Matias Lammens said: "The search warrant arrived during half-time and of course with a court order from a judge we are not going to deny their entry. They came in and when the game finished they communicated with the player.
"He wasn't expecting this; we'll ask for his release and the club will respect his contract."
Migliore appeared in court on Monday but refused to testify against Mazzaro, who is second in command of the Boca ultras group and has been on the run for three months. Mauro Martin, the barra brava's leader, was arrested in relation to Cirino's murder last month and is awaiting trial. Lawyers insist there are no links to Migliore outside football.
Migliore's lawyer, Matias Morla, said: "The crime he is charged with allows for his release. The next 48 hours will be crucial. We will then need to wait for a decision by the judge, which could take 10 days. In the meantime, he will remain in prison."