Someone claiming to be from the Mexican drug cartel allegedly responsible for the abduction of four Americans and the killing of two of them has condemned the violence and purportedly will turn over its own members who were involved to authorities.

In a letter obtained by The Associated Press through a Tamaulipas state law enforcement source, the Scorpions faction of the Gulf cartel allegedly responsible for abducting the Americans apologized to the residents of Matamoros, the Mexican woman who died in the shooting and the four Americans and their families.

Drug cartels have been known to issue communiques to intimidate rivals and authorities, but also at times like these to do some public relations work to try to smooth over situations that could affect their business.

"We have decided to turn over those who were directly involved and responsible in the events, who at all times acted under their own decision-making and lack of discipline," the letter reads, adding that those individuals had gone against the cartel's rules, which include "respecting the life and well-being of the innocent."

A photograph of five men face down on the pavement and bound accompanied the letter, which was shared with The Associated Press by the source on condition that they remain anonymous because they were not authorized to share the document.

The state of Tamaulipas is the stronghold of the Gulf Cartel, one of the oldest and most powerful of Mexico's criminal groups. But the cartel has lost territory and influence in recent years to its rivals, according to the think tank InSight Crime.

State officials did not immediately publicly confirm having new suspects in custody.

A separate state security official said that five men had been found tied up inside one of the vehicles that authorities had been searching for, along with the letter. That official also spoke on condition of anonymity because they were not authorized to speak about the case.

Last Friday, four Americans crossed into Matamoros from Texas so that one of them could get a cosmetic surgery procedure. Around midday they were fired on in downtown Matamoros and then loaded into a pickup truck.

Authorities located them Tuesday morning on the outskirts of the city, guarded by a man who was arrested. Two of the Americans were dead, one was wounded and the other was unharmed.

A woman who traveled to the Mexican border with the four Americans said that she warned police when the group didn't return on schedule. 

Cheryl Orange told the Associated Press via text message that she was with Eric Williams, Latavia McGee, Zindell Brown and Shaeed Woodard. McGee was scheduled to have cosmetic surgery in the Mexican city of Matamoros last Friday, and the other three were meant to cross back into the United States and reconvene with Orange in the Texas city of Brownsville within 15 minutes of dropping her off.   

According to a police report reviewed by CBS News, the group was reported missing by Orange on Saturday. 

The police report says Orange believed McGee was planning to undergo a gluteal augmentation in Matamoros. Orange did not have any information about the medical office McGee was going to, nor did she know which route her friends were taking to get to there.  

Orange told police that the only reason she stayed in the group's Brownsville hotel room was because she had forgotten her identification and couldn't cross the border. She had their luggage, she told police, and had tried contacting the group several times, but their phones seemed to be "turned off." 

In:
• Drug Cartels
• Mexico
• Kidnapping
• Crime