The captured head of the Zetas drug cartel has filed for legal protection over claims that he is at risk of torture or isolation during his detention, court officials said.

A court official who visited Miguel Angel Trevino, alias "Z-40," determined that the drug kingpin has no grounds to complain and a judge will likely reject his bid in the coming days, one of the sources said.

Trevino has been held at a facility of the federal attorney general's office in Mexico City since he was nabbed by Mexican marines in a pre-dawn operation in northeastern Mexico last Monday.

Trevino -- himself accused of torture and murder -- filed four complaints against the attorney general's office for "the possible practices of torture, isolation and mistreatment that may have taken place or may take place," an official said.

But the court official who visited him "saw that there is no isolation, nor mistreatment or torture, or the risk that this could happen," the official added.

The legal protection Trevino is seeking aims to protect the rights of detainees but it would not lead to his release, the official said.

Rights groups have accused authorities of committing abuses and torture against prisoners since troops were deployed to crack down on drug cartels in 2006.