Zimbabwe - Six people have been arrested in central Zimbabwe after a 26-year-old rhino was poached, an official said on Monday.
The male rhino was killed on Friday evening in the Midlands Black Rhino Conservancy.
Its body was discovered in thick bush on Saturday morning "when our monitors went back to look for him", said Dave Strydom, who is the conservator.
"Somebody had crept up on him," Strydom added. "He was one of our top bulls."
The animal was named elsewhere as Tangarira. The conservancy is near the town of Kwekwe, about 200km from the capital Harare.
The bull was due to be dehorned a week before the killing but the operation had to be postponed. The timing of the killing has raised suspicions that it may have been an inside job.
A website for the Sebakwe Black Rhino Trust says 15 farmers joined together to form the 85 000-hectare Midlands conservancy.
The organisation had until this incident held a proud record of having had no rhinos poached in six years.
AWARE Trust, an animal welfare group run by Zimbabwean vets, called the killing "a crying shame".
At least six rhino have been killed by poachers so far in Zimbabwe this year, three of them from the Save Valley Conservancy in the south-east of the country. Zimbabwe has fewer than 500 black rhino and around 300 white rhino.