A man's body was found in a pool of blood at Mumbuuni market in Maara Sub-county, Tharaka-Nithi, on Tuesday morning.
Residents who found Franklin Mbuthia Kangori, 35, dead outside a shop called police.
Maara divisional police commander Johnston Kabusia said the body had deep cuts in the back and stomach, caused by a sharp object.
“This is a murder case. The man may have been killed using a panga or any other sharp object,” he said.
Mr Kabusia promised the residents that police would do everything possible to find and punish Mr Kangori's killers.
While assuring confidentiality, he urged them to assist police with the investigation.
Mr Kabusia noted that murder cases were on the rise but said police and other authorities were taking action.
“I urge our people to always support police in fighting crime by giving them information that can help in investigations or to avert crimes,” said the OCPD.
Two weeks ago, an 18-year-old house girl was found murdered and her body dumped in a banana plantation in Gaketha village in the same sub-county.
Ms Naomi Kawira's body had deep cuts in the head, right hand and the back.
Police are yet to arrest the culprits but their probe so far suggests the woman may have been killed outside her bedroom in which she lived by somebody who knew her.
There was no break-in but door to her house was wide open.
Police took her mobile phone for use in the investigation.