North Carolina ? A Marine suspected of killing a pregnant comrade told friends he would flee to Mexico to avoid being convicted of raping her, and investigators said Wednesday they are working with Mexican authorities to track him down.

A wide-ranging manhunt for Cpl. Cesar Armando Laurean began last week, after authorities said he fled North Carolina and left a note in which he admitted burying the body of Lance Cpl. Maria Lauterbach, but said she committed suicide. The 20-year-old had accused him of rape.

Investigators found Lauterbach’s burned remains, and those of her child, in a fire pit in Laurean’s backyard and concluded she did not kill herself.

Court documents filed this week by the FBI state that Laurean, 21, told members of his Marine Corps unit he would flee to Mexico if it appeared he would be found guilty of rape. Laurean’s wife also told authorities she believed he would head to Mexico if he was in trouble.

Laurean, 21, of Las Vegas, is a naturalized U.S. citizen who was born in Mexico and still has some family there, authorities said.