Murder scene in Tamaulipas

A wave of violence in northern Mexico has been attributed to a bloody struggle for control of the Gulf Cartel, suggesting long running internal disputes and the loss of key leaders have led to a breakdown in the organization's structure.

In this past week alone, at least 35 people have been killed in clashes in a string of cities across the state of Tamaulipas, reported Proceso.

The violence began on April 4 with an assault on a hotel in Ciudad Mier, before spreading to the cities of Tampico, Miguel Aleman, Reynosa and Matamoros.

According to anonymous security forces sources consulted by EFE, the cause of the confrontations is a war for control of the Gulf Cartel, which has divided into factions following the recent arrests of two leading commanders.

One of these factions is controlled by the family of Osiel Cardenas Guillen, who led the cartel in its heyday, and is based in Matamoros, while the other faction controls the metropolitan area of Tampico, according to Proceso.

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Once one of Mexico's most powerful drug cartels, the Gulf Cartel has been in decline since 2010, when its armed wing, the Zetas, turned on their former masters. Shortly after, the group split into two competing factions, one known as the Metros, led by Jorge Eduardo Costilla Sanchez, alias "El Coss," and the other, the Rojos, which stayed loyal to the Cardenas family.

Since then, the group has been hit hard by war with the Zetas, and the arrests of leader El Coss in 2012 and his successor Mario Ramirez Treviño, alias "X20," in 2013, on the Metros side, and of Mario Cardenas Guillen, alias "El Gordo," on the Rojos side in 2012.

If the current reports of infighting are correct, it would suggest a continuation of the conflict begun years earlier, with the Cardenas family leading the Rojos against their rivals.

SEE ALSO: Gulf Cartel News and Profile

However, with no clear leadership emerging since the arrests, and the recent capture of another commander touted as a possible leader, the cartel may have broken down to such an extent that even this could be a simplification, and it is possible even more factions are disputing control.

The situation is further complicated by the enduring conflict with the Zetas in Tamaulipas, who themselves have been undergoing a process of division and fragmentation following the loss of key leaders.

In this new, ever more fractured criminal landscape, it is likely Tamaulipas will continue to be ravaged by violence, as the remnants of the two cartels battle over the remains of their fallen criminal empires.