The two surviving Americans in a group of four violently abducted last week in Mexico returned to U.S. soil Tuesday, one of them with a leg wound not considered life-threatening.

Mexican authorities said the two other members of the group traveling for cosmetic surgery were killed Friday after getting caught in a drug cartel shootout in the border city of Matamoros in Tamaulipas state, just south of Brownsville, Texas.

Tamaulipas Gov. Americo Villarreal said the Americans, traveling in a white minivan, had crossed the border only 2 1/2 hours before the shooting occurred. A 33-year-old woman not linked to the group was killed by a stray bullet, he said.

Attorney General Irving Barrios said no ransom was demanded and all signs point to the U.S. travelers being the victims of mistaken identity. They were kidnapped after the attack and located Tuesday around 8 a.m. in a house outside Matamoros, Barrios said. A suspect who was standing guard over them has been arrested.

Barrios said the two deceased Americans – identified by authorities as Shaeed Woodard, 33, and Zindell Brown, in his mid-20s – are undergoing autopsies to determine the time and cause of death. They will be returned to the U.S. after that.

Both survivors, one of them unharmed, were rushed to the U.S. and taken to a hospital after a convoy of Mexican ambulances and SUVs was escorted by Mexican military Humvees, armored vehicles, state police and the National Guard. The injured survivor was identified as Eric Williams. The other one is Latavia Washington McGee.

Justice Department vows ‘relentless’ pursuit of those who perpetrated attack

Federal investigators believe the Americans were mistakenly targeted, and there was nothing to indicate they were in Mexico for any other purpose than a medical procedure, a person familiar with the investigation said.