Three female mountain gorillas were found shot dead this morning in the Democratic Republic of Congo's Virunga National Park.
Another three gorillas are missing, and park rangers fear they may have also been killed.
The slaughter deeply shocked the rangers and conservationists who work to protect the endangered gorillas in a park that has been ravaged by civil strife for years.
"This is a disaster," said Emmanuel de Merode, director of WildlifeDirect, a conservation group based in the Democratic Republic of Congo (DRC) and Kenya that supports the rangers working in Virunga.
Park staff and WildlifeDirect officials stationed in Virunga's Bukima camp said they heard gunshots coming from inside the dense forest around 8 p.m. on Saturday night.
"We conducted a search this morning," de Merode said.
"The rangers went up first and located the gorillas. Then we went up about mid-day with a team of rangers.
"The gorillas were all quite close together. They had all been shot," he said.
One of the dead females was the mother of a three-month-old baby gorilla, while another victim was the mother of a two-year-old animal. The third gorilla killed was pregnant.
The gorillas killed all came from the so-called Rugendo family of 12 individuals, headed by a silverback gorilla named Rugendo.
The family is one of several groups of gorillas that live on the Congo side of the sprawling Virunga National Park, which straddles the border of Congo, Rwanda, and Uganda, and are visited from the Bukima camp, Kazinform quotes National Geographic News.
More than half of the gorillas' population, estimated at about 700, is found in Virunga. The rest live in forests in Rwanda and Uganda, Kazinform quotes National Geographic News.
The park lies in the heart of one of the most troubled regions of Africa.
The DRC is struggling to emerge from a civil war that has left an estimated 4 million people dead and dates back to the genocide in Rwanda in 1994.
Today the area is home to a vast array of rebel militias, government soldiers, foreign troops, and villagers who are unsympathetic to the rangers protecting the park. Poaching remains a major problem.
Early this year two silverback gorillas were killed within the span of two days in the same area as where the latest killings occurred. The incident sparked an international outcry of support for the embattled gorillas.
Those apes appeared to have been butchered for their meat. One of them had had his dismembered body dumped in a latrine.
Last month a female gorilla from the Kabirizi family was found shot to death in the park.
Another female from that family has been missing ever since and is presumed to have been killed too.
The "execution-style" killing of the gorillas last night was identical to the killing last month, de Merode said.
He believes the slaughter was meant to send a chilling message to the rangers to get out of the park.
"We don't think it was the villagers who did it," he said. "This was deliberate … an act of sabotage."
De Merode said there is evidence from the site of the killings linking the incident to the area's lucrative charcoal trade.
Virtually all of the charcoal that is supplied to the nearby city of Goma—worth an estimated U.S. $30 million a year—is made from wood harvested illegally inside Virunga National Park, he said.
"Last year Rwanda put a ban on any charcoal production within Rwanda," de Merode said.
"This means that whole country's charcoal is largely supplied from Congo," he added. "This has put a lot of pressure on the park."