A box containing a severed human head and two hands has been sent to the boss of Kenya's police commission with a note saying "you are next," an official said.
The parcel was left in a flowerbed outside the body's headquarters in Nairobi. It was addressed to Johnston Kavuludi, who was appointed head of the watchdog a year ago and was tasked with rooting out corruption within the police force.
Colleagues say it is possible the threat came from police officers who feel threatened by Kavuludi's reforms.
"It is someone who is trying to intimidate the chairman and the entire department," said Murshid Mohamed, who serves on the governmental body under Kavuludi. "It could be criminal gangs, it could be terrorist groups, or it could be errant police officers who might be affected by the vetting of the entire service."
But Mohamed said authorities would not deterred by the threat to Kavuludi's life.
"Was Kavuludi shocked on seeing the head? For sure. When you find something as nasty as this you get concerned," Mohamed said. "But after the initial reaction he told us that we are not going to relent. We are confident in our security and the entire administration has been backing the commission. When people resort to such measures it can only mean we are on the right path."
In a survey last month by international watchdog Transparency International, Kenyans rated their police force as the country's most corrupt institution, with 95 percent describing it as either "corrupt" or "very corrupt". It also found 70 percent of Kenyans reported paying a bribe in the past 12 months.
"Bribery has permeated the ranks of the police service over the years to the extent that it has attained a sense of normalcy,” Samuel Kimeu, Transparency International’s executive director in Kenya, told the Institute for War and Peace Reporting.
Despite these figures, a Kenya Police spokesman said Kavuludi's reforms were improving the situation.
"By virtue of that office, it gives him the authority to look at the police service in several ways," the spokesman said. "He has been in the office close to one year, and with his new structures criminal control has been improved."
He said these changes could explain why Kavuludi was sent the box of body parts.
"Criminals are never happy when things are getting better. And to a large extent crime has been dealt with since Kavuludi came into the police commission."
Nairobi Police Chief Benson Kibui agreed. "Reforming the police is a fight that has been taken up on all fronts," he said.
The reforms aim to transform Kenya's police force into that of a "proper democracy," commission member Mohamed said. "The entire package of reforms is to looking at improving efficiency and rooting out corruption," he said. "This is our vision and our goal."
Officers said they were determined to track down whoever was behind the grisly delivery.
"The most important thing now is not that Kavuludi was sent a head, but that someone was murdered," the police spokesman said.
"The victim has been identified positively. He was a civilian reported missing by the family."
The Daily Nation reported the body parts were matched to a torso found on a farm on the outskirts of Nairobi and that they were believed to belong to a 34-year-old man from Mombasa who had gone missing.