In March 1989, a University of Texas student named Mark Kilroy did what countless other college students do on spring break: he headed to South Padre Island to party and hang out on the beach with his friends and the thousands of other kids who trekked to southern Texas. Except 21-year-old Mark Kilroy never returned home. And when investigators dug into Kilroy’s disappearance, they uncovered a mysterious, deadly cult that believed in two things: Satanism and drug smuggling.

Mark Kilroy and his friends spent the first couple days of their vacation enjoying the beaches of South Padre Island. Then, the night before he disappeared, Kilroy and his friends ventured across the U.S./Mexico border at Brownsville, Texas to go explore Matamoros, Mexico. The group decided to head to Matamoros again the next night, March 13, for some bar hopping.

Kilroy became separated from his friends when they attempted to cross the border back into Brownsville after the bars in Matamoros had closed. Huge crowds of college kids were streaming back into the U.S. on foot across a bridge at the same time as Kilroy and his friends. Kilroy’s companions searched for him for a couple of hours before they decided he had probably gotten lost in the masses and crossed back into Brownsville without them. But the next morning there was still no sign of him. His friends contacted the authorities and reported Mark Kilroy missing.

Photo Credit: NY Daily News

What Kilroy’s friends did not know is that he had been snatched off the street in Matamoros the night before amid all the confusion caused by thousands of intoxicated college students walking back toward the border crossing. A man in a truck called to Kilroy, asking if he needed a ride, but as Kilroy approached the vehicle, two men grabbed him and forced inside. Kilroy briefly escaped his captors and ran away, but was caught again, handcuffed, and thrown into a different car.

Kilroy was driven to a remote ranch outside of Matamoros called Santa Elena where he was kept prisoner in the car the entire night. The following day, a group of men led Kilroy to a field on the ranch property. There, one of the men brutally murdered Kilroy with a machete. The executioner was the group’s leader, a 26-year-old named Adolfo Constanzo.

Photo Credit: Bizarrepedia

Mark Kilroy’s murder was not Constanzo’s first killing, nor was it a pointless act of violence, at least in Constanzo’s view. He was the leader of a Satanic cult that operated on the Santa Elena ranch. The cult sold and smuggled drugs, and Constanzo  “sacrificed” people in a ritual meant to protect himself and the other drug dealers who followed him. Sometimes he killed rival drug dealers, and sometimes he took the lives of random strangers, like Mark Kilroy. Constanzo’s ceremony also entailed mutilating his victims’ bodies, and after he died, Kilroy’s brain was boiled and his limbs were cut off. His butchered body was then buried.

Mark Kilroy’s disappearance caused quite a stir. His story was featured on America’s Most Wanted. More than two weeks passed, but authorities repeatedly hit dead ends. Finally, on April 1, 1989, police received a break in the case when Mexican police officers followed a vehicle that sped through a routine traffic checkpoint. The vehicle drove to the Santa Elena ranch. Officers quickly investigated the ranch and found small amounts of drugs and bizarre materials relating to the occult. Eight days later, police returned to the ranch and arrested all those who were present. When questioned about the missing American college student, a ranch worker told police that he had seen Mark Kilroy on the property.

One of the other men arrested was a drug dealer and a follower of Adolfo Constanzo. Under questioning, he admitted that he helped abduct Mark Kilroy and that Constanzo demanded that the young American be killed as part of a cult sacrifice. The man also admitted that Constanzo had killed several other people at the ranch. Police raided the ranch and discovered 15 dead bodies, including the corpse of Mark Kilroy. Police also found cocaine, marijuana, and a cache of weapons. But they didn’t find Adolfo Constanzo. He had fled to Mexico City with four of his devotees.

Photo Credit: NY Daily News

Nearly a month passed after the raid on Santa Elena, and Constanzo was still hiding out in an apartment in Mexico City. Slowly, police were able to zero in on the area of the city where Constanzo was hiding. Acting on surveillance and tips, police finally determined Constanzo’s exact location, and on May 6, 1989, police surrounded his apartment building. The cult leader noticed the commotion on the street and opened fire on the officers with a machine gun. But Constanzo could not keep the police at bay once he ran out of ammunition, so he ordered one of his followers to kill him and another associate. Rather than face what would certainly have been a life in jail, Constanzo chose death.

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