It wasn’t just post-match fighting that got out of hand.

Egyptian fans clash with riot police Wednesday in Port Said, Egypt. (STR/AP)

According to The Guardian, a number of suspicious details at the match support the theory: For one, the gates to the playing field were left open after the hometown team El-Masry won, and the police patrolling the area did not prevent fans from storming the field. The numbers of riot police at the match were far less than are usually present. Large numbers of weapons managed to get inside the stadium, despite not having been allowed in the past, and they appeared especially in the hands of El-Masry fans.

When fans of the losing team, Al-Ahly, tried to escape the violence, they found exit gates closed. Police are reported to have stood by as those fans were crushed, doing nothing to help. Footage of the riot shows the police idly standing by.

Many Egyptians are now pointing out that security forces have a reason to act out against the Al-Ahly team — or at least their fans.

Al-Ahly has a somewhat new fan base of Ultras, or fanatic sports fans. During the uprising against the Hosni Mubarak regime last year, Ultras were often at the forefront of the protests.

“It is difficult to avoid the impression that the chaos had been at least partly-engineered to teach a painful lesson to the Ultras - and by proxy the Egyptian liberals,” writes Martin Chulov in the Guardian.

Prominent Egyptian activists like Mona Eltehawy also thinks it was intended as a lesson for the Ultras:

Repeating from earlier today: #SCAF & police hate #Ultras football fans bec r active in #Jan25. #PortsPortsaidMassacre #AhlyThu Feb 02 04:21:56 via Twitter for iPadMona Eltahawy

An account in Arab English-language weekly Al-Ahram from Ahly fan Ahmed Ghaffar, who claims to have been present at the riot, also bolsters the theory:

“Police opened the way for hordes of Masry fans to reach us… when Ahly fans tried to run away they found exits which are normally open at the end of the match were locked.”

Online, outraged Egyptians shared photos of the violence, of children who had died in the riot, and of parents crying over the death of their child.

 Mass rallies are being organized Thursday in Cairo, where many are expected to take to the streets to protest the lack of action by security forces. Parliament has also called an emergency session to discuss the incident.

More world news coverage:

- U.S. seeks to end Afghan mission next year

- Audacious engineer goes for Amazon oil

- Iran warns currency speculators

- Read more headlines from around the world