Isaria Anael Meli has been looking for his grandfather’s remains for more than six decades.
He believes the skull ended up in a Berlin museum after his grandfather, Mangi Meli, along with 18 other chiefs and advisers, were hanged by a German colonial force 123 years ago.
After all this time, a German minister has told the BBC the country is prepared to apologise for the executions in what is now northern Tanzania.
Other descendants have also been searching for the remains and recently, in an unprecedented use of DNA research, two of the skulls of those killed have been identified among a museum collection of thousands.
It is rare to find an acacia tree on the lower slopes of Mount Kilimanjaro. Its twisting branches reach above the steep road and stand out among the denser lush vegetation.
At one time, it shaded a market for the villagers of Tsudunyi, a part of what is now called Old Moshi, who lived off the fertile land and enjoyed the cooler temperatures that the higher altitude brought.
But this focal point for the community became the scene of a great tragedy. Despite the peace of the natural surroundings today, its impact has reverberated down the decades.
It was here on 2 March 1900 that, as the descendants tell it, one-by-one the 19 men were hanged. They had been hastily tried the day before, accused of plotting to attack the German colonial forces.
Germany’s claim to this part of the continent was formalised at the Berlin Conference of 1884-1885. The European powers divided up Africa between them, without the people living there having any say in what happened.
Mangi Meli, the most prominent mangi, or chief, among those who were killed, had in 1892 successfully defeated the German forces. That success was later reversed and by the end of the 19th Century, the Europeans were keen to stamp their authority on this part of what was known as German East Africa.
They wanted to make an example of Mangi Meli and other local leaders who may have been planning an uprising.
The humiliation did not end there.
While most of the torsos are believed to be buried in a mass grave somewhere near the tree, their heads were at some point removed, packed up and sent 6,600km (4,100 miles) to the German capital. In some cases the complete skeletons were shipped.
When speaking about what happened to his grandfather, Mr Meli does not sound angry, but there is a sadness in his voice and a sense of bewilderment that this was allowed to happen.
The lively 92-year-old was told about the killing of Mangi Meli by his grandmother, who he says was forced to watch the execution, and explains that the chief came to him at night telling him that he would return one day.
“Always, always, always he was coming to me in my dreams,” he says.
His floppy sun hat and twinkling eyes when he smiles disguise his tenacious personality.
Since at least the 1960s, Mr Meli had been writing to the German and Tanzanian authorities urging them to look for the remains of his grandfather.
He says officials tried to put him off by telling him that relevant records had been destroyed during World War Two. But Mr Meli was not deterred.
“Visitors are always crying: ‘Tell all the people of Germany to return the skull.’
“They kept it somewhere just because they thought the Mangi Meli family were small people – believing that they could do what they wanted. But remember that this skull is needed by the whole country – not me, myself, only.”
There is a sense of profound loss that goes beyond the idea that this was a historical injustice.
Mangi Meli was a chief from the Chagga ethnic group – one of the most prominent in modern-day Tanzania. For the Chagga people, as well as others in the region, the idea that the head was separated from the body and then taken away from the land is deeply disturbing.
In Chagga culture the dead are supposed to be buried in the homestead so they can continue to watch over the living. It is believed that the failure to do that could have consequences down the generations.
“If we leave the skulls in Germany, the spirits will be tormenting these families,” explains Gabriel Mzei Orio, who founded the Old Moshi Cultural Tourism Enterprise in part to highlight Chagga culture to the rest of the world.
He is standing under the acacia tree in Tsudunyi, next to a memorial to those who were killed there.
“The spirits are saying: ‘You know where we are and you don’t bring us to our homeland and you know we were taken in a cruel way.'”
Simulango Molelia, the grandson of another victim of the executions – Mangi Molelia – believes his family is being haunted by the chief’s spirit.
The 69-year-old sits in his shady homestead surrounded by banana plants, the staple food in the region and the source of the traditional beer that the family brews. As is the custom here, the graves of his mother and father are in the homestead – a tradition denied to his grandfather.
“Many things were affected by the killings,” he says in a soft voice, suggesting that it was like roots of a tree being attacked.
“When Mangi Molelia was killed, the family lost its wealth. Up to now things are not good.”
But for those who took the body parts more than 120 years ago, this was of no concern.
Museums and other institutions in 19th and early 20th Century Europe and North America amassed large collections of skulls and other human remains.
This was partly driven by huge interest in the now-discredited science of phrenology. It was based on the idea that someone’s fundamental characteristics were reflected in the shape of their skull.
In some cases it took on a racist element, with researchers trying to establish a racial hierarchy. As a consequence people began collecting skulls from across the world.
German anthropologist Felix von Luschan, who headed the Africa and Oceania department of Berlin’s Royal Museum of Ethnology, was keen to acquire remains from Germany’s empire as well as other European colonies.
“Even an amateur can procure anthropological material,” he wrote in 1899 in an instruction manual for collectors.
“Any occasion to rescue a large number of skulls preferably with lower jaw should be zealously used…
“In certain circumstances a very superficial cleaning is necessary. Sometimes this entails only the removal of flesh and drying – the rest can be done in Europe.”
In March 1901 – a year after the executions – Von Luschan wrote directly to First Lt Moritz Merker, one of those in charge of the German forces in Kilimanjaro.
The letter was about some cultural artefacts, but as a final paragraph he wrote: “I use this occasion to inquire whether it would be possible for you to ask natives in an amicable way to hand over some skeletons of Maasai and Chagga to us.”
Merker responded the following month, saying that some remains were on their way and a shipping note from the port of Dar es Salaam states that two boxes of Chagga and Maasai skulls had been sent.
It is not clear if Mangi Meli’s skull was among the shipment, but it seems likely that this was when some of the remains of the executed men were transported, according to German researcher Konradin Kunze, who has been heavily involved in the campaign to find them.
The bones then went into Von Luschan’s vast archive, including the S-collection (“s” for skull), which in the four decades up to his death in 1924, grew to 6,300 samples.
Some of his private collection was sold by his widow to the American Museum of Natural History in New York. This included the entire skeleton of one of those hanged in 1900.
But for the rest, down the decades, they passed through several institutions and in 2010 they ended up in the care of the Berlin-based Prussian Cultural Heritage Foundation (known by its German initials SPK) – but much of the documentation that went with it had been lost.