The video, which was filmed by an unknown person on a mobile phone, showing villagers attacking a kneeling, defenceless elephant, hitting him with sharp objects until it died.
Kenyans were calling on the national wildlife service on Twitter to arrest the perpetrators.
The Kenya Wildlife Service (KWS) said in a statement that the incident occurred in mid-2018 near the Ncoroiboro-Imenti forest, about 240 kilometres north of the capital Nairobi.
The organisation added that the rangers found the dead elephant at the time but had no leads about who had killed the animal.
It is unclear why the video was only posted on social media this week and who had initiated the campaign.
“That now KWS is in possession of the video, the culprits will be arrested with help from the local authorities.
Watch the video below:
“Perhaps the saddest thing about the brutal killing of an elephant in Kenya is that it happened in 2018 and we didn’t know about it.
“Paula Kahumbu, a Kenyan conservationist and director of Wildlife Direct, wrote on Twitter that the death went unnoticed by most of us,’’ the service said.
The conflict between humans and wildlife is not uncommon in the East African nation, especially in communities living in close proximity to national parks.
Maurice Nyaligu, an elephant programme coordinator at the World Wide Fund for Nature Kenya (WWF), told DPA that there were possibilities that the elephant was retracing its migratory pathway when it found that humans had already encroached on their land.