Nigerian police say they have found the bodies of 41 men with their throats cut in a northern area that is notorious as a hideout for criminal gangs.
Eighteen bodies were found in a river on Sunday while 23 others were discovered in a nearby forest in the Zurmi area of Zamfara state, police commissioner Kenneth Ebrimson said on Tuesday.
Police arrested four suspects after searching the bush area and also found machetes and guns, he told reporters in Gusau, the state capital.
He said the suspects were identified as members of a widely-feared local vigilante group “who decided to carry out the extra-judicial killings”.
Police believe the victims were gang members who had been involved in cattle rustling and kidnapping.
But local residents were unable to identify any of the bodies, suggesting they were not resident in the area, he said.
Farming and cattle herding communities in Zamfara have for years been terrorised by gangs of cattle thieves and kidnappers who raid villages, steal cows and abduct locals for ransom.
As a hideout, the gangs use the Ruggu forest which straddles Zamfara, Katsina and Kaduna states.
The attacks have prompted villagers to form militia groups for protection but they, too, have been accused of taking the law into their own hands and killing suspected bandits.
Those killings attract reprisals from motorcycle-riding criminal gangs, who carry out indiscriminate killings and arson in retaliation.
In April the Nigerian government deployed troops to Zamfara to fight the gangs while the police outlawed the vigilantes to end the tit-for-tat killings.