Three bodies found in northern Mexico have been identified as those of three siblings from Texas who had been missing since mid-October. The three Americans, who were of Mexican descent, had been visiting their father in El Control, a small town outside Matamoros city in the northeastern border state of Tamaulipas, when they disappeared along with a fourth person on Oct. 13, according to the Associated Press.

The father, Pedro Alvarado, confirmed from photographs that the bodies were those of his daughter, 26-year-old Erica Alvarado Rivera, and his two sons, 22-year-old Alex Alvarado and 21-year-old Jose Angel Alvarado. The bodies were badly decomposed when authorities recovered them Wednesday. Investigators were able to match tattoos on the bodies to those of the three missing siblings. Clothing discovered with the bodies also matched that of the Texas siblings.

A fourth body discovered alongside the others was thought to be that of Erica Alvarado’s Mexican boyfriend, 32-year-old Jose Guadalupe Castaneda Benitez, but it's unclear if the identity of the fourth body has been confirmed. Investigators said it could take 24 to 48 hours for DNA tests to confirm the identities, the AP reported.

Witnesses told family members that the siblings had had a confrontation with the local Hercules police unit, who provide security for city officials. Matamoros, like other border cities in Tamaulipas, has not had a municipal police force for years after the federal government dismantled them in an effort to wipe out police corruption.

Members of Hercules reportedly took the three siblings, along with Erica Alvarado Rivera’s boyfriend, away after they were seen around 12:30 p.m. on Oct. 13 pushing Erica Alvarado Rivera and Benitez outside a roadside restaurant near El Control. It is unclear what happened after that.

Tamaulipas is one of Mexico’s most dangerous states and is known for its violent and powerful drug cartels. Dozens of people were killed or went missing over a two-month span this past summer due to rivaling factions, according to the Los Angeles Times. Federal authorities have pledged to ramp up security in Tamaulipas, yet kidnappings remain prevalent in the state, according to the U.S. Department of State, which has warned U.S. citizens against traveling there.