Senior Superintendent Dennis Pena, Palawan police director, identified the casualties as Marcial Cadungog, Jose Ramos, Teodoro Garcia, Marlon Sarasa, Jun-jun Bonbon, Cornelio Cormas, Bimbo Unding and Toto Johore, alias Toto Vilma.
Pena said, Toto Johore, a member of the local cult group Commando Brotherhood, threw the fragmentation grenade in the middle of a public dance at the plaza of Rizal town.
Police said most of the casualties were onlookers.
Investigation said that at around 1 a.m.on Friday, Johore arrived in Barangay Canipaan carrying a shotgun.
His colleagues, who were also members of the cult, chided him and told him not to bring his weapon to the dance.
Embarrassed, Johore left the plaza and went home but returned shortly with a grenade.
Upon seeing the grenade, his colleagues tried to grab it but the pin was removed during the scuffle.
A few seconds later, the grenade exploded killing eight persons including Johore.
Police said 25 others were seriously injured and rushed to the Ospital ng Palawan in Puerto Princesa, Rio Tuba Nickel Hospital in Bataraza, and Puerto Princesa Cooperative Hospital for treatment.
Probers said the Commando Brotherhood was linked to the Philippine Benevolent Missionaries Association (PBMA) of Ruben Ecleo but it was not ascertained if the group in Palawan was an affiliate.