MEXICO CITY — The body of a U.S. teenager was found in the trunk of a burned-out car in western Mexico along with the bodies of two other youths, prosecutors said Tuesday.

An employee of the state prosecutors' office in Michoacan state said the car holding the remains of the three young men was found on the side of a rural road on Christmas Eve. The young men had last been seen on the night of Dec. 23.

The employee, who was not authorized to be quoted by name, identified the dead American as 18-year-old Alexis Uriel Marron.

Prosecutors are looking into robbery as a possible motive because none of the men's possessions were found in the car. But the area has also been the scene of bloody turf battles between drug gangs. The Knights Templar and Jalisco New Generation cartels are believed to be active in the area.

Marron was a student at Rolling Meadows High School in suburban Chicago and had relatives throughout the area. Marron's cousin, Danila Zendejas, told Chicago television station WLS that she considered him to be a brother.

"He loved his nieces," she said. "And he didn't have time to get to one of them, to see her grow."

U.S. State Department spokesman Noel Clay said the agency was working with embassy officials to get more information. Mexican Consulate officials in Chicago said they were aware of reports of Marron's death and were ready to help family if requested.

A memorial service for Marron was planned Tuesday evening in his home town of Rolling Meadows.

The U.S. Embassy in Mexico City said in an email message that it was aware of reports that Marron had been killed, but was working to get more information.

The other two victims were identified as Mexican men aged 21 and 24. All three were from, or had family in, the nearby village of Quiringuicharo, Michoacan. Their bodies were found on a two-lane road near the border with Jalisco state.

Earlier in December, two other bodies were found in a burned-out vehicle on the same stretch of road. The victims have been identified as two Mexico City residents, but there was no immediate information on the motive in those killings either.