On Friday March 3, four U.S. citizens were kidnapped after a brazen attack carried out by multiple gunmen in the northern Mexico border city of Matamoros. On Tuesday, Mexican and U.S. officials said two of the four U.S. citizens were found dead and two are alive.

Mexico's security secretary identified the surviving Americans as Latavia "Tay" McGee and Eric James Williams. Earlier, CBS News learned the two Americans killed were identified as Zindell Brown and Shaeed Woodard.

Officials previously confirmed that a Mexican citizen was killed in the initial attack.

Mexican federal and state officials escorted the two surviving Americans to an international bridge at the U.S.-Mexico border, the attorney general in Tamaulipas, the state where Matamoros is located, confirmed in a tweet posted Tuesday afternoon. 

McGee and Williams received medical treatment in Brownsville, Texas. Williams reportedly received a gunshot wound to the leg.

The four Americans traveled to Matamoros from Brownsville on Friday in a rented white minivan, the FBI said.

The agency's San Antonio Division office said in a statement Sunday that the vehicle came under fire shortly after it entered Mexico.

Here is what else we know so far about the case.

What footage and photos from the scene show

A video posted on Twitter on Friday appears to show the moment the Americans were kidnapped, CBS News correspondent Christina Ruffini reports.

In the video, one woman is forced by men armed with guns to climb into the bed of a white pickup truck. The men then proceed to drag two people into the vehicle.

The first woman is walking and sits in the back of the truck; the other two people seem to be unresponsive, but their condition is unknown. The video appears to show some of them may be wounded.

Photographs from the scene viewed by the AP show a white minivan with the driver's side window shot and all of the doors open. The van sits on the side of the road after apparently colliding with a red SUV. The photos show people lying in the street next to the van surrounded by rifle-toting men.

The photos seem to match the video posted online, which was taken from another angle.

What officials have said about the incident

U.S. Ambassador to Mexico Ken Salazar said in a statement Monday that the Americans were kidnapped at gunpoint and that an "innocent" Mexican citizen died in the attack. 

During a news briefing on Tuesday, State Department spokesperson Ned Price confirmed that the two survivors from the attack had been returned to the U.S. He declined to share additional information about the investigation into their abduction. 

"The investigation is in its earliest days," Price said. "I understand we may have more to share from the FBI at the appropriate time."

The Americans were found as a result of joint search operations, according to the attorney general in Tamaulipas, but how officials ultimately located and rescued them remains unclear.

Mexican President Andrés Manuel López Obrador said that one person was in custody in connection with the abduction, the Associated Press reported.

Mexican authorities found the Americans in a wooden shack — guarded by a man who was arrested — in the rural Ejido Tecolote area east of Matamoros on the way to the Gulf area called "Bagdad Beach," according to the state's chief prosecutor, Irving Barrios.

What were the Americans doing in Matamoros?

Zalandria Brown, of Florence, South Carolina, told The Associated Press she'd been in contact with the FBI and local officials after learning that her younger brother, Zindell Brown, was one of the four victims.

Zalandria Brown said Zindell Brown, who lives in Myrtle Beach, South Carolina, and two friends were with a third friend who was going to Mexico for "tummy tuck" cosmetic surgery. 

Zalandia Brown said the four knew of the dangers in Mexico and Zindell kept saying they shouldn't go.

A woman who traveled to the Mexican border with the four Americans who were kidnapped 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 Williams, McGee, Brown and Woodard. McGee was scheduled to have cosmetic surgery in Matamoros last Friday, and the other three were meant to cross back into the United States and reconvene with Orange in Brownsville within 15 minutes of dropping her off. 

Instead, the four friends were attacked shortly after arriving in the city. The FBI told CBS News that they were fired upon by drug cartel factions, and the white van they were driving crashed. 

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

The U.S. State Department's travel advisory for Tamaulipas state warns U.S. citizens not to travel there. However, being a border city, U.S. citizens who live in Brownsville or elsewhere in Texas frequently cross to visit family, get medical care or shop. It's also a crossing point for people traveling to other parts in Mexico.

For years, a night out in Matamoros was also part of the "two-nation vacation" for spring breakers flocking to Texas' South Padre Island.

But increased cartel violence over the past 10 to 15 years has frightened away much of that business. 

What is behind the violence in Tamaulipas

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.

Someone claiming to be from the 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 apologized to the residents of Matamoros, the Mexican woman who died in the shooting and the four Americans and their families.

"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 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.

On March 3, the U.S. Consulate issued an alert about violence in Matamoros and local authorities warned people to shelter in place. The alert also reminded U.S. citizens that this particular part of Mexico is a "Level 4: Do Not Travel," which is the highest warning in the U.S. State Department's travel advisory system.  

The consulate in Matamoros has posted at least four security alerts since February 2020, warning of drug cartel violence, crime, kidnappings and clashes involving armed groups.  

Victims of violence in Matamoros and other large border cities of Tamaulipas often go uncounted, because the cartels have a history of disappearing the bodies of their victims. Local media often avoid reporting on such incidents out of safety concerns.

-CBS News correspondent Jeff Pegues contributed reporting.

In:
• Drug Cartels
• Mexico
• Crime