Shock waves reverberated across the soccer world when images of horrifying violence emerged from last weekend's Liga MX match between Queretaro and Atlas.

In the second half of Saturday's game at Queretaro's Estadio Corregidora, play was stopped when fans began to pour onto the pitch after fights between barras supporters' groups had broken out in the stands. Outnumbered as the visitors, Atlas fans were chased by Queretaro ultras wielding impromptu weapons such as seats and pieces of the stadium's advertisement boards.

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Crowds escaped via the players' tunnel on the pitch amid the chaos, with family members removing the jerseys of their children so as to not be identified as Atlas fans. Videos and images quickly emerged on social media of individuals lying unconscious in pools of blood, while being kicked and stripped of their clothes.

With a noticeable lack of a sufficient security presence (and even footage of officers standing by amid the fights), the violence left 26 injured with three people in critical condition. Two remain hospitalized as of Thursday. No deaths have been officially reported by authorities.

FIFA and CONCACAF condemned the events, while authorities confirmed that 14 individuals have since been arrested. Five state officials were suspended, including three people responsible for planning and preparations.

On Tuesday, Liga MX president Mikel Arriola and Mexican Football Federation president Yon de Luisa laid out punishments to the two clubs involved and unveiled new league-wide protocols on safety.

And after a short pause in league games, the 2022 Clausura season picks up again this Friday -- with Queretaro kicking off the action at Necaxa with no fans in attendance.

Nonetheless, questions continue to linger. In order to provide some clarity, ESPN explores what is known about one of the darkest days in Mexican soccer, what has yet to be resolved and whether enough has been done to prevent further tragedies.

Additional reporting by ESPN Mexico and ESPN Deportes.

What happened? | Who's to blame? | Will Queretaro stay in Liga MX? | How did Liga MX respond? | Are these safety measures enough? | What about the '26 World Cup? |

Has this happened before and what led to it?

While the overwhelming majority of Liga MX matches occur without any sort of incident, there has been a string of matches in recent years where rivalries among fans have turned violent. Outside of the period from 2020-21 impacted by a drop in attendances due to the coronavirus pandemic, fan brawls at specific matches have occurred at least once a year since 2013.

Last weekend's game wasn't the first time Queretaro and Atlas fans had been part of such an incident. A 2019 match between Queretaro and regional rivals San Luis was suspended after several spectators were injured in clashes. Atlas fans have also fought with fans of their Guadalajara rivals Chivas several times in recent years.

As for matches directly between Queretaro and Atlas, there is a history of animosity dating back to 2007, when Queretaro were relegated to the second division after a 2-0 loss to Atlas, with additional incidents between the two sides occurring in 2010 and 2013.

Tensions appeared to have calmed down in recent years between two sides, but they returned on Saturday. A small smoke bomb, thrown onto the field right before kickoff, would foreshadow the turmoil that would surface. With a scoreline at 1-0 in Atlas' favor, fights broke out near the 60th minute.

As the brawls began to escalate near the 63rd minute, hundreds of fans rushed onto the pitch to seek safety from the altercations -- quickly leading referee Fernando Guerrero to call off the game. Atlas' squad made their way off the field behind Guerrero, while many Queretaro players stood their ground with the futile hopes of minimizing the impact of the riot. Most notably, Queretaro goalkeeper Washington Aguerre roamed around with his arms constantly raised, willing a peace that wouldn't arrive.

Who's to blame and what is still unknown?

One question is how or why the fights started. In a report from ESPN Mexico, which cites a document from Liga MX officials, members from Queretaro's barras are highlighted as possible antagonists. However the same report includes a statement from an anonymous person in attendance who claims that it was a group of Atlas fans who instigated the situation.

Regardless of which side started the fight, it raises the issue of the alarming lack of a security presence and why there weren't more officials around. With a reported total of 14,463 in attendance -- which could have been higher in a stadium with a capacity of 34,000 that hosted 1986 World Cup matches -- it's frightening to think of what would have happened if the venue were close to the maximum 80% capacity that was permitted for the building that weekend.

According to Liga MX's security manual, matches are to be classified by risk level, taking into consideration factors such as historic rivalries, previous incidents between clubs' fans, and the stadium's size and infrastructure. It recommends for "two security elements per 100 spectators." Queretaro state governor Mauricio Kuri had stated that the number of security officials "was insufficient" and in an interview with TUDN said that 290 security guards of the 400 requested were provided.

ESPN Mexico has reported that the company in charge of providing security for Saturday's game has not responded to messages and has deleted its Facebook posts.

No deaths have been officially reported after initial accounts by other news outlets said there had been some at the stadium, while some fans circulated unverified statements of knowing people who had died at the scene. Government officials have not confirmed any deaths, but after seeing the bloodshed and genuinely disturbing scenes that emerged on social media from the attacks, it makes sense why skepticism persists.

Will Queretaro be kicked out of Liga MX? Will fans be allowed back?

Queretaro will remain a Liga MX club, with Arriola saying on Tuesday following the owners meeting that Queretaro will stay in order to avoid impacting the ongoing 2022 Clausura season and to maintain the employment of players and staff.

However, the league did dole out punishments for the club and its ownership group. The club will play home games behind closed doors with no fans in attendance for one year. That also applies to its youth and women's squads. Furthermore, Queretaro's barras are suspended for three years from attending home games, with a one-year ban on attending away matches.

Queretaro's ownership group, made up of Gabriel Solares, Adolfo Rios, Greg Taylor and Manuel Velarde, will be suspended for five years from league-related activities. A fine of 1.5 million pesos ($70,450) will also be levied.

Grupo Caliente, which also owns fellow Liga MX side Tijuana and was the previous owner of Queretaro, will once again control the club and must sell it by the end of this year. If it is unable to do so, Queretaro will go under Liga MX's stewardship.

Atlas-affiliated supporters' groups will be banned from attending away matches for six months. Lastly, the match will officially be recorded as a 3-0 Atlas win.

What about other Liga MX teams?

In that same meeting on Tuesday, Arriola laid out new protocols when it comes to barras -- or "animation groups" as he referred to them -- for all Liga MX teams. First, no away barras will be allowed at any matches although he did not specify for how long (aside from the Queretaro and Atlas groups). In addition, only registered members can enter supporters' group sections at home games, although there was no specifics on how they would be identified. No underage individuals will be allowed in those sections.

However, starting for the 2022-23 season, IDs will be utilized to register members of supporters' groups, as well as facial recognition technology for all in attendance at stadiums. Additionally, clubs can no longer offer aid to supporters' groups, such as providing financial help or tickets.

State, local and municipal police will now provide security at Liga MX games, as opposed to the private security often used at matches. A joint security and intelligence group formed by the league and the FMF will also be created to supervise clubs.

Any individuals who are proved to have been involved in the violence from the incident will be given a lifetime ban from all Mexican soccer stadiums -- a rule that applies to all Liga MX fans who are found taking part in assaults, going forward.

Although Arriola noted that the latest measures implemented "will mark a before and after in the protocols that must be observed and followed," it's difficult to believe that hostilities will vanish. Away fans, but not supporters' groups or barras, can still purchase tickets. As seen in a few of the games listed above, conflicts can also make themselves present just outside of stadium grounds.

Will these punishments prevent further violence?

Suspending the involved teams' supporters' groups, on the surface, seems logical -- but stills falls short in the face of preventing violence in the future. In other countries, groups are carded by teams for identification purposes so troublemakers can be rooted out. In the wake of Saturday's events, only two teams (Santos Laguna and Atlas) will immediately implement fan IDs in a manner similar to what FIFA created in order to exert control over who attends World Cup games.

Why the league isn't pushing for that to be immediately mandatory across all 18 teams is logical: It costs money. Owners would then pass the expense onto fans. Sure, fans would bristle at more expensive tickets and having to register in order to attend games at first, but in the long run, the cost is minimal compared to ensuring their safety.

Arriola and De Luisa assured they'd work even closer with government officials to avoid a repeat of what happened. However, therein lies part of the problem. A cursory view of even some of the less violent images from last weekend will show a passive, almost lackadaisical approach from the security officials as events unfolded. One video showed Queretaro backup goalkeeper Antonio Rodriguez rushing over to an officer and pointing to brawls erupting in the stands. The officer shrugged. Another video saw a security guard chatting away on his phone while a group of fans ran behind him en route to the clashes.

Police officers clearly need better training for large-scale events in Mexico. They need to be more engaged at their jobs. A 2018 government poll showed just 38.8% of Mexicans considered their local police force to be effective. This, of course, extends to providing protection at soccer matches. Security checks are routine for fans at venues like Estadio Azteca in Mexico City, where attendees are often required to take off their belts and even surrender coins before entering the premises. In Queretaro, the image of a fan pulling a knife from his sock in order to cut the netting off goalposts is a clear indicator that supporters' groups are not held to the same standard. Whether they rely on private security or local law enforcement, Liga MX and the teams must improve the safety of matches for all in attendance.

Lastly, much has been made of the unintended effects of potential league disaffiliation for Queretaro. The players, both men and women, would see their professional careers damaged by such a move. Dozens of administrative employees would be left without a job overnight. Arriola himself lamented the previous instances in which teams like Veracruz and Chiapas have been shuttered, with those affected unable to claim severance years after the fact.

And while having the current administration forfeit ownership in lieu of disaffiliation seems fair on the surface, it prompts another question. Will the banned former partners get their money back? And with previous owner Grupo Caliente taking over the club again, does this mean it will profit twice from the sale of Queretaro?

Could Mexico lose World Cup 2026 hosting duties?

This incident comes ahead of two men's World Cup qualifiers at Estadio Azteca later this month, and the CONCACAF W Championship in July in Monterrey, which will serve as the qualification tournament for both the 2023 Women's World Cup and the 2024 Olympics. And of course further down the road, Mexico is set to co-host the 2026 men's World Cup alongside the U.S. and Canada.

Asked about whether those hosting duties were in jeopardy, Arriola admitted it could have been "at risk if Mexico didn't resolve and didn't show a capacity" of addressing the issue, before adding the planning "can continue very forcefully going forward."

Mexico therefore will not likely lose hosting duties over what occurred in Queretaro, but it's easy to deduce why FIFA -- dealing with its own fraught image -- will worry about what happened.

The sport's world governing body has already chastised Mexico's soccer federation over its failure to deal with the anti-gay chant largely present at men's national team games, with fines and stadium bans over the past five years. The presence or even the threat of violence at Mexican stadiums therefore only adds to those woes. Some fans have threatened to use the chant at future games to voice their displeasure over the Queretaro punishment, as Arriola and De Luisa previously suggested would happen earlier this year in protest of the lack of promotion and relegation within the league.

As such, if issues such as physical violence in the stands begin to permeate the sport in the country, FIFA already has the perfect excuse to take action against the FMF, via the chant. Should FIFA truly want to dole out discipline and reverse course on its 2026 World Cup hosting decision, that is likely the road for it to take. And while FIFA and CONCACAF cannot directly intervene in Liga MX's domestic matches, special attention will no doubt be placed on the behavior of fans in games that do fall under their purview.