The murder of a Mexican border state prison guard by suspected Gulf Cartel gunmen at her home appears to be revenge for three homicides inside a detention facility. Prior to the killing, cops arrested four other prison guards in connection with the murders.

The guard’s murder took place Sunday in Ciudad Victoria, Tamaulipas. Two gunmen barged into the home of 50-year-old Magdalena Balboa and shot her several times in front of her family. No arrests have been made.

Days before the murder, the Gulf Cartel sent messages on social media warning about payback for the recent murders of three top commanders inside the state prison in Ciudad Victoria.

Last week, authorities in Tamaulipas confirmed the murder of former Matamoros plaza boss Oscar Antonio “La Droga” Lopez Sandoval, regional boss in Jimenez, prison boss Jose Luis “Pepillo” Sanchez Guevara, and former state policeman-turned-cartel member Evaristo Eduardo Nunez Caballero. Initial information revealed by state authorities suggested no foul play.

Later in the week, the Tamaulipas government announced the arrest of four prison guards on charges of murder and abuse of office. Law enforcement sources revealed to Breitbart Texas the four guards allegedly gave a group of inmates access to the three bosses who then choked them to death. The four guards and others then allegedly helped cover up the case.

Ildefonso Ortiz is an award-winning journalist with Breitbart Texas. He co-founded Breitbart Texas’ Cartel Chronicles project with Brandon Darby and senior Breitbart management. You can follow him on Twitter and on Facebook. He can be contacted at Iortiz@breitbart.com

Brandon Darby is the managing director and editor-in-chief of Breitbart Texas. He co-founded Breitbart Texas’ Cartel Chronicles project with Ildefonso Ortiz and senior Breitbart management. Follow him on Twitter and Facebook. He can be contacted at bdarby@breitbart.com.     

“Francisco Morales” “J.A. Espinoza” and “J.C. Sanchez” from Tamaulipas contributed to this report.