Three top Mexican government officials, including one former state governor, have been arrested in the past month in connection with drug trafficking charges.

Another former Mexican state governor was arrested on Saturday in relation to money laundering and racketeering charges.

Edgar Veytia was arrested on March 29 while serving as attorney general for the Mexican state of Nayarit. The federal indictment said that Veytia was nicknamed “Diablo,” and was part of a massive drug distribution operation that was worth up to $250 million.

Attorney General Jeff Sessions met with Mexican Attorney General Cervantes Andrade on Tuesday, and the two discussed the arrest of Veytia, and agreed to work on his case and identify assets to be seized.

A week after Veytia’s arrest on April 5, the Department of Justice announced the indictment of Ivan Reyes Arzate, a commander with the Mexican Federal Police. Arzate was involved in a joint-operation with U.S. officials into a Mexican drug cartel, and he allegedly tipped off cartel members when the Drug Enforcement Agency received warrants to intercept their phone calls.

The indictment said that Arzate was photographed meeting with the alleged head of a Mexican cartel that he was helping.

Then on April 11, the ex-governor of the Mexican border state of Tamaulipas, Tomas Yarrington, was arrested in Italy after five years of hiding. Yarrington allegedly received millions of dollars in bribes from Mexican drug cartels. The bribes Yarrington took allowed two major cartels, Gulf and Zeta, to operate freely in the border state.

Sessions and Mexico’s attorney general put out a joint-statement Wednesday about Yarrington’s arrest, in which the two agreed that the U.S. will get priority for the prosecution of Yarrington and that he will then be temporarily surrendered to Mexico.

Another Mexican governor was then arrested on Saturday. Javier Duarte, the former governor of Veracruz state, was caught in Guatemala and faces charges of embezzlement. During his time as governor Veracruz suffered from violence as cartels fought over territory.

Both Duarte and Yarrington were members of the Institutional Revolutionary Party (PRI), which Mexican President Enrique Pena Nieto is a part of.