A purported drug cartel hit man has been arrested in connection with the disappearance and alleged killing of 43 college students in southern Mexico in September, authorities said Friday.

Felipe Rodriguez, alias "The Brush" or "The Stubborn One," is a member of the Guerreros Unidos gang and believed to be the "material author" of the killings, the Federal Prosecutor's Office said in a statement. It did not give further details.

Officials say the 43 students were rounded up by police Sept. 26 in the Guerrero state city of Iguala and handed over to Guerreros Unidos gang members, who allegedly killed them, burned the bodies at a trash dump and threw the remains into a river.

So far only one of the students has been positively identified by DNA testing on human remains, and family members and others have expressed doubts about the official account of the disappearances. They continue to press for information on what happened to the other 42 and have asked investigators not to close the case.

Authorities suspect the former mayor of Iguala, Jose Luis Abarca, of ordering the kidnappings. Abarca has been in custody since November along with his wife, Maria de los Angeles Pineda, who has been charged with organized crime and money laundering.

More than 90 suspects have been arrested in the disappearances, most of them municipal police officers.