They were identified as Kunle Olomofe 45; Adewale Abiodun 40; Akinola Sunday 69 and Oluwadare Idowu, 67.
Sources said they were arrested while trying to severe the head of a tipper driver just buried at the cemetery.
A family member said: “It was when we caught them in the act which led to their beating that we discovered that they were in possession of other humans heads.
“We immediately contacted men of the Special Anti-Robbery Squad (SARS) who came to pick them up.”
Spokesperson for the Ondo State Police Command, ASP Tee-Leo Ikoro said investigation has begun into the matter.
Ikoro said efforts were on to arrest other members of the syndicate.
“The ongoing investigation will reveal everything, particularly other members of the gang.
“From what we have found out, it shows that it’s not their first time. It’s something they have been doing, it’s a routine thing.
“Like we always hear, very many days for the thief, one day for the owner. I think this time, their cup is full,” Ikoro stated.