Alabama law enforcement officials say that an illegal immigrant and an immigrant in the United States on a green card are responsible for the brutal murders of a grandmother and her 13-year-old special needs granddaughter in what investigators say is violence related to Mexican drug cartels.

AL.com reports:

A 13-year-old Huntsville girl was beheaded after she witnessed her grandmother assaulted with a knife and left to die on the ground in a cemetery, court testimony revealed.

The grandmother, 49-year-old Oralia Mendoza, was allegedly connected to the Sinaloa Mexican drug cartel which is widely considered to be the largest and most powerful drug trafficking organization in the world.

Investigator Stacy Rutherford told a court on Thursday that Mendoza traveled to Georgia in early June to pick up a batch of methamphetamine with Israel Palomino, 34, Yoni Aguilar, 26, and Leticia Garcia.

Rutherford testified that Mendoza and Garcia were both connected to the Sinaloa Cartel and Palomino suspected that something went wrong during the drug pick up when he discovered after the alleged drug pick up that Mendoza removed the SIM card from her phone. ABC 31 reports:

He also found a text message sent to an unknown woman during the Georgia drug run, investigators said. In that text, Mendoza asked the woman to pick up her granddaughter from Palomino's wife because she was afraid for their lives, they said.

Authorities say that Mendoza and Aguilar lived together and were dating and that she had dated Palomino in the past.

After discovering the text message, Palomino and Aguilar allegedly woke up Mendoza during the night and told her that they were taking her and her granddaughter to somewhere safe, investigators said.

The two men then reportedly took her to a cemetery where she began to argue with Palomino who then stabbed her and left her there to die. The two men then took the granddaughter to a separate location where they allegedly decapitated her.

Several days after the murders, authorities had Aguilar and Palomino in custody. Aguilar allegedly confessed to the crimes.

Investigators said that they recovered two knives that they believe were used as the murder weapons and that both of the men's cellphones gave off signals in the area of the crimes during the time they were committed.

Press Release

Homicide Investigation pic.twitter.com/yN2YKxntnL — Madison Sheriff AL (@mcsosheriffAL) June 14, 2018

It is not clear whether Palomino and Aguilar have direct associations with any Mexican drug cartels or association with any street gang outside of their connections to Mendoza.

The Atlanta Journal-Constitution reports that Immigration and Customs Enforcement (ICE) has lodged a detainer request against Aguilar since he is in the country illegally.

AL.com adds that during her testimony, Rutherford said that the girl who was murdered had special needs.