The Mexican state of Tamaulipas has dismissed its head of security following the discovery of 145 bodies in mass graves earlier this month.

墨西哥塔毛利帕斯州在本月早些时候发现一座埋有145具尸体的乱葬岗，该州警察局长因此被免职。

Former army Gen Ubaldo Ayala Tinoco has been replaced by another former soldier, Capt Rafael Lomeli Martinez.

The state governor said the new chief would improve coordination¹ with the army and federal police in the fight against drugs gangs.

The killings² have been blamed on the Zetas drug cartel.

More than 20 suspected cartel members have been arrested in connection with the killings, including the alleged³ mastermind of the massacre⁴（大屠杀） .

But 16 state policemen have also been arrested on suspicion of protecting the criminals.

Battleground

Outgoing Tamaulipas security chief Gen Ayala said he was stepping down because the state government had failed to provide increased pay and better equipment for the state police.

His replacement⁵, Capt Lomeli, was previously⁶ head of the Federal Police in Nuevo Leon, another northern border state where drug-related violence is rife⁷（普遍的，流行的） .

He said he was committed to pacifying⁸ Tamaulipas, which is the scene of a bloody⁹ battle between the Zetas and the rival Gulf¹⁰ cartel, who are competing for control of drug smuggling¹¹ routes into the US.

The mass graves containing 145 bodies were found in the municipality of San Fernando, near the US border.

Most of the victims are thought to have been abducted¹² from long-distance buses travelling north to the US border.

The motive¹³ for the murders is unclear, but there is speculation¹⁴ the cartel gunmen may have killed men who refused to join their ranks.

The bodies of 72 Central and South American migrants were found in the same area last year.