Mexico’s Zetas cartel has reportedly claimed responsibility for last week’s shooting at the Blue Parrot nightclub during The BPM Festival.

The shooting left at least five dead and injured about three times that number, but no concrete information has been released about the gunmen until now. According to Fox News and a local publication, four “narcoblankets” brought a sign to Playa del Carmen on Tuesday morning that read the following text (translated from Spanish):

“This is a sign that we are already here because you didn’t align PHILLIP -BPM, it is the beginning we are going to cut the heads of Golfos, PELONES and chapulines, Atte [Sincerely] el FAYO Z from the old SCHOOL”

According to Semanario Playa News, the “FAYO-Z” signer could be a regional leader of the Zetas cartel, Rafael del Angel Velez Morales, and “Phillip -BPM” can be in reference to BPM co-founder Phillip Pulitano. Investigators are reportedly llooking into whether the banner is in reference to The BPM Music Festival or one of its organizers.

Feds say that the Zetas have been in the state for years and especially in Cancun itself, where the cartel was blamed for the firebombing of a bar that left eight people dead in 2010.

The Associated Press also recently reported that a new shooting took place at a state prosecutors’ office in Cancun. According to AP, four people were killed, including three attackers and one police officer, and five suspected attackers were taken into custody.

It’s unclear whether the two shootings are linked.