Mexican authorities were investigating the death of two Arizona women after their bodies were found on Friday along a highway in Sonora, Mexico, the northern state that borders Arizona.

Around 10:30 a.m., Mexican authorities received reports of two women dead inside an overturned vehicle on the Sonoyta-Caborca highway, the exterior of the vehicle marked with bullet holes, the Sonora Attorney General said in a news release on X, formerly Twitter.

The attorney general only released the last name of the two women, identifying them as 72-year-old and 82-year-old Arizona residents originally from Caborca, a city in northern Sonora.

Mexican investigators believed the two women had been attacked on the road. Authorities found a stolen Ford F-150 truck, along with firearms, ammunition and ballistic vests believed to be related to the shooting, according to the news release.

On Tuesday, a spokesperson with the U.S. Department of State confirmed the death of the two women, both U.S. citizens.

“We extend our deepest condolences to the family and loved ones of the deceased,” said the spokesperson.

The State Department was “closely monitoring the situation,” but declined to provide further details.

The Federal Bureau of Investigation was assisting Mexican authorities with the case, a spokesperson with the Phoenix field office said.