Police in Brazil have arrested 18 people in connection with the killing of an indigenous leader last November.

Gunmen shot Nisio Gomes in Mato Grosso do Sul and took away his body, which is still missing.

Police only confirmed his murder last week, after finding that a witness who claimed to have seen him alive had been paid to give false evidence.

Mr Gomes, 59, led a Guarani group which had returned to its land after being evicted by ranchers.

A spokesperson for the federal police in Ponta Pora, in the southern state of Mato Grosso do Sul, said they had arrested 10 people belonging to a private security firm suspected of having been hired to attack Mr Gomes's camp.

The spokesperson said another eight people, six of them landowners, were being held on suspicion of masterminding the attack.