A coconut has been detained by Maldivian police on suspicion of vote-rigging in a key presidential election.

The coconut, described as "young", was found near a school that will be used as a polling station on Saturday on the remote Kaafu atoll, one of the hundreds of islands that comprise the Indian Ocean archipelago state.

Though the population of the Maldives is Sunni Muslim, continuing belief in magic is widespread in rural areas. Coconuts are often used in rituals and inscribed with spells.

The hundreds of thousands of international tourists who travel to the Maldives usually stay in isolated resorts and have no contact with local people other than staff.

The local Minivan news website reported that police "took the coconut into their possession" around 7.05am on Tuesday, after they received a complaint about the suspicious fruit near the school on the Guraidhoo Island, which lies 130 miles from the capital, Male, and has a population of around 2,000.

"The 4in coconut had a [Koranic verse] written in Arabic [on it] and was lying on the ground near the school, easy for the public to see. It seems like it was a joke, just a prank, so that people will become aware," Minivan quoted a source on Guraidhoo saying.

Minivan said its source had suggested the coconut "was a lesson for islanders not to practise black magic in an attempt to influence voting, and that the polling area would be closely monitored to prevent such activities from occurring".

Earlier this year, school authorities on Guraidhoo resisted using their buildings as a polling station, citing previous instances when problems had been caused by magic. Their fears were only partly allayed when the national election commission said it would accept responsibility "if anyone falls under a spell or comes down ill".

The election has been bitterly contested, with Mohammed Nasheed, the former president, who claims he was ousted last year in a coup, taking on one of the Maldives' biggest businessmen, the outgoing president and the half-brother of former dictator, Mamoun Abdul Gayoom.

Nasheed, an internationally respected human rights and climate-change campaigner, hopes to win outright this weekend and avoid a run-off second round of voting.

A magician summoned by police established that the coconut was innocent, local officials have said. No arrests have been made.