As Mexican authorities investigate possible motives behind a fatal shooting at a nightclub in Playa del Carmen on Monday, a chilling message has appeared in the coastal resort city that appears to take aim at one of the organizers of the music festival that was hosting an event at the venue that night.

Just over 24 hours after the shooting and stampede at the Blue Parrot nightclub that claimed the lives of Canadian bouncer Kirk Wilson and four others, an image of a message spray-painted on banners around the town specifically naming the BPM festival and someone associated with it is circulating widely in local media outlets.

"This is to show that we are here, for not falling in line, Phillip-BPM. This is the beginning. We are going to cut the heads off of Golfos, Pelones and Chapulines," reads the message, referring to rival gangs and drug dealers. The message is signed "El Fayo Z, old school."

The BPM festival — which stands for Bartenders, Promoters and Musicians — was founded and organized by Torontonians Philip Pulitano and Craig Pettigrew. It's presumed that the "Philip" in the message is Pulitano, who, a source close to the organizers tells CBC News, had the role of co-ordinating the terms of the festival with the cartel.

'This is to show that we are here, for not falling in line, Phillip-BPM. This is the beginning, we are going to cut the heads off of Golfos, Pelones and Chapulines,' reads the message claiming responsibility for the massacre, signed 'El Fayo Z, old school.' (Semanario Playa News Aquí y Ahora (Translates: the Weekly Beach News Here and Now/Facebook))

Mexican officials confirmed to CBC News that the banner, or narcomanta, was found hanging in Playa del Carmen, a resort town south of Cancun on the Yucatan peninsula. They would not confirm a connection to the notorious Zetas drug cartel active in the state, saying their investigation is ongoing.

But CBC News has learned from the source that Monday's shooting wasn't the first incident of violence against the festival involving the cartel this year.

The source, who CBC News is not naming to protect their safety, also says the Zetas cartel increased demands on BPM organizers this year. But the organizers, who previously had a decent relationship with the drug cartel, ignored those demands, according to the source.

"They can turn on you in a second," the source said.

BPM, which has been holding events in Playa Carmen annually since 2008, announced at a show during its 10-day stretch that this year would be the festival's last in the Mexican city and that it would be moving to Brazil or Portugal.

Local police not confirming cartel connection

Organizers with BPM have gone into hiding following the shooting, the source says. Attempts by CBC News to reach the organizers have not been successful.

In an official statement posted to its website, BPM said it has been working closely with local authorities Seguridad Publica/Policia Turistica throughout the festival to ensure the safety and security of its visitors.

"We are overcome with grief over this senseless act of violence, and we are co-operating fully with local law enforcement and government officials as they continue their investigation," it said, adding members of the BPM security were killed trying to protect patrons inside.

CBC News reached out to Global Affairs to inquire if they were assisting BPM organizers to safely leave Mexico.

"Consular officials have been actively assisting Canadians and their families who have sought or needed assistance. Due to privacy considerations, we can provide no further specific information," spokesperson Jocelyn Sweet responded in an email.

But while local police have not confirmed a connection to the Zetas cartel, Quintana Roo state Attorney General Miguel Angel Peche isn't ruling out that demands may have been made.

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"Either they didn't reach an agreement over protection payments, directly extortion, or it may be that somebody did not allow them to sell drugs inside [the club]," Pech said.

"Perhaps the strongest hypothesis is that this person had gone there to demand they comply with protection payments," he added at a news conference.

'It's extortion'

According to B.C.-based Mexico security expert and former police officer Walter McKay, Monday's brazen shooting smacks of the Zetas. McKay has worked as a security consultant in Mexico for several years.

McKay says doing business in Playa del Carmen has long come with a price and that anyone operating there has to play by the unofficial rules.

"It's a necessary evil. If they do not want to have somebody or a couple of people to come into event and shoot it up, they have to pay," McKay said.

"This is traditional Zeta territory and has been for a long time. So clearly what had happened was that they were supposed to be paying a fee — a bribe — in order to operate.

"It's extortion, is what it is."

Federal authorities say the Zetas have been operational in the state for years, especially in Cancun itself, where the cartel was blamed for the firebombing of a bar in which eight people died in 2010.

Drug cartel influence in the state as a whole goes back at least to the 1990s under Governor Mario Villanueva, who was later convicted in the U.S. of involvement in large-scale drug smuggling.