EAST PALO ALTO (KRON) — A brutal and bloody cockfighting ring was busted in East Palo Alto, and the suspect behind the illegal operation has been arrested on Thursday.

All 56 roosters had to be euthanized. East Palo Alto police have identified Aldenni de Jesus Trujillo Santiago as the suspect arrested.

Police were originally called out because a neighbor was complaining about an aggressive dog on the loose.

They found out the dog was not aggressive towards people, but instead, was trying to attack roosters and hens in a nearby yard.

According to police, officers were dispatched at 3:50 p.m. on March 23 to the 1200 block of Cypress Street after a neighbor called to report an aggressive dog in the neighborhood. The dog was determined not to be aggressive toward people, but was trying to attack roosters and hens in the rear yard.

Peninsula Humane Society & SPCA spokeswoman Buffy Martin Tarbox said that PHS/SPCA investigator Christina Hanley was already en route to the residence to investigate reports of cockfighting when she received a call from East Palo Alto police notifying her of the aggressive dog.

Two illegal outbuildings, illegal wiring, and a potentially illegal addition to the house were also discovered at the residence, police said.

According to Hanley, most of the roosters had been “dubbed,” a painful process consistent with cockfighting in which their combs, wattles, and earlobes are cut off.

The PHS/SPCA reported that the suspect surrendered 56 roosters, many of which had wounds three to four weeks old. All of the surrendered birds had to be euthanized since many were suffering from cockfighting-related injuries or were considered too aggressive for adoption.

Trujillo Santiago was arrested on suspicion of animal cruelty, cockfighting, and possession of cockfighting materials.Bay City News contributed to this report.