Omar Adan Buul, the head of the Gumarey sub-location in Wajir county, was kidnapped on Friday by jihadists who had raided the area and "lectured the locals", according to Kenyan media reports.
"It is true the chief who went missing last week on Friday has been found dead. His head was dumped on the road but the rest of the body has not been found," a local police officer said on condition of anonymity.
Another police officer said "we have collected the head and taken it to the mortuary".
"This is the work of Al-Shabaab... we are looking for the rest of the body or the parts, we hope it wasn't taken to the other side," he added, referring to over the Somali border.
Al-Shabaab claimed responsibility for the "execution" through their Shahada News Agency, according to the US monitoring group SITE.
The group said it had taken the chief prisoner during an attack that seized control of a Kenyan police outpost, a claim that has not been confirmed.
The Al-Qaeda-linked group has been waging a violent insurgency across Somalia seeking to unseat the internationally-backed government in the capital Mogadishu.
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They were driven out of Mogadishu by government forces backed by 20,000 African Union peacekeepers in 2011.
But the group still controls swathes of territory outside the cities, from where they launch attacks against government targets, as well as occasionally crossing the border to carry out raids in Kenya.
Al-Shabaab has ramped up the intensity of its attacks in Kenya in recent years, including several major assaults as far as the capital Nairobi, which have left nearly 300 dead.
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