A Mexican official overseeing security in Chihuahua, Mexico was arrested Tuesday in connection to a massacre that left three American women and six children dead last month, according to the New York Post.

The group found itself ambushed by cartels as they were making their way through Sonora, Mexico to visit family in the United States.

Fidel Alejandro Villegas Villegas, the Director of Public Safety in Janos, was arrested by the Office of the Special Prosecutor for Organized Crime Investigation (Seido) for his suspected connection to Juarez drug cartel, according to the Herald of Chihuahua.

The suspect is now being held in Mexico City, according to the Post. Mexican officials have made several other arrests in connection to last month’s attack.

President Donald Trump signaled last month that he would take action against the ruthless Mexican drug cartels by designating them “Foreign Terrorist Organizations,” in an interview with Bill O’Reilly. Earlier this month, however, the President wrote on Twitter that he’s not as ready to act on his earlier statement.

“All necessary work has been completed to declare Mexican Cartels terrorist organizations,” Trump wrote on Twitter. “However, at the request of a man who I like and respect, and has worked so well with us, President Andres Manuel @lopezobrador we will temporarily hold off this designation and step up our joint efforts to deal decisively with these vicious and ever-growing organizations!”