Reports from Mexico City say a man arrested on suspicion of killing the brother of the central bank governor last August has been set free.

Sergio Diaz Aguilar is said to have been released for lack of evidence.

The governor's brother, Alejandro Ortiz Martinez, was shot dead outside his house in the Mexico City suburb of Lomas de Chapultepec - police at the time said he was apparently trying to stop thieves stealing his car.