A pair of illegal alien siblings pleaded guilty to charges that they murdered or helped murder one of their co-workers at Goma Dairy Farm in Sanilac County, Michigan, last year.

Illegal alien siblings Francisca Vargas-Castillo and Leobardo Torres-Castillo, both from Mexico, took plea deals this month after being charged for the murder of their 43-year-old dairy farm co-worker, Bricia Flores-Rivera, in September of last year.

According to prosecutors, Vargas-Castillo beat Flores-Rivera with a stick before stabbing her to death in a trailer in Marlette Township, Michigan. After murdering her, Vargas-Castillo got her brother Torres-Castillo to help dump the woman’s body in a ditch.

Witnesses for the prosecution said that Vargas-Castillo believed that Flores-Rivera was attempting to poison her children and sleep with her husband.

Vargas-Castillo pleaded guilty to second-degree murder, concealing the woman’s death, and tampering with evidence. Likewise her brother, Torres-Castillo, pleaded guilty to assaulting the woman, concealing the woman’s death, and tampering with evidence.

Vargas-Castillo could be sentenced to life in prison, while Torres-Castillo is looking at a minimum sentence of 25 years in prison.

A law enforcement official confirmed to Breitbart News that the siblings had been living in the U.S. illegally but that federal immigration officials were unclear as to when the two first illegally arrived in the country.

John Binder is a reporter for Breitbart News. Follow him on Twitter at @JxhnBinder.