An unknown group of assailants broke into El Salvador's National Zoo and brutally beat Gustavito the hippopotamus, leading to his untimely death on Sunday.

According to the zoo director Vladan Hernriquez, they noticed Gustavito acting strange on Thursday. He would not eat and stayed the entire day in his enclosure. Noticing this, they checked upon the beloved animal and were shocked to found punctures, lacerations and bruises on his body, including his feet and his cheek. It is likely that he got his injuries while he was defending himself from the inhumane assailants.

Sydney Morning Herald notes that initial investigation revealed rocks and pieces of metal found in the area. Authorities suspected that that 15-year-old hippo was assaulted with "blunt and sharp objects" on Tuesday night.

Read Also: 500 Animals Die in Cumbria in a Span of 4 Years, UK Zoo May Face Repercussions

Gustavito was considered one of the zoo's iconic animals. He was taken to the zoo 13 years ago.
To mourn his death, people who often visit the zoo left some flowers outside the establishment, which has been closed since the incident.

"We're angry," said Carmen Rogel, an El Salvador resident told Associated Press. "We didn't know they had killed Gustavito and were surprised when we arrived and the gate was closed."

The Standard reported that authorities are still trying to figure out who broke into the animal's enclosure while security at the zoo was doubled to prevent the vicious incident from happening again. The zoo is closed until further notice.

The Ministry of Culture asserted that they will never buy exotic animals again and instead focus their efforts in their indigenous species.

CDA News noted that El Salvador is one of the most violent country today, with an average of 14 murder cases per day last year and 10 this year. While gang violence is widespread, Gustavito's case provoed more outrage.

Hippopotamus has an average lifespan of 50 years. They are the third largest land-living mammal, with length that could stretch to 13 feet. They are considered vulnerable as they are often targeted by humans for their ivory and fat, which are deemed valuable in the black market.

Read Also: Armed Men Attack Animal Orphanage, Kill Baby Rhinos Before Brutally Removing Their Horns