Underworld figures fixed the results of Rio de Janeiro's carnival parade this year, according to Brazilian police. Press reports suggest that top criminals used bribes and a hitman to buy and intimidate members of the carnival jury.

The fixing allegations centre on Anisio Abraao David, 69, the honorary president of the Beija-Flor (hummingbird) samba school, whose empire includes a penthouse apartment on Copacabana beach complete with a swimming pool with a hummingbird motif on the bottom.

According to extracts from a federal police report, published this week in O Globo newspaper, "some individuals who worked as carnival jurors and refused to accept benefits from Anisio were threatened or had their relatives threatened with death if the Beija-Flor school did not win the 2007 carnival". In February Beija-Flor were crowned carnival champions.

Claims that Rio's carnival procession was fixed emerged in April after the police cracked down on a gambling racket allegedly involving the payment of bribes to Brazilian judges. During a raid on an apartment in northern Rio, agents found 4m reals (£1.04m) hidden behind a fake wall.

Shortly after the crackdown, known as Operation Hurricane, a parliamentary inquiry was set up. Yesterday, as the allegations grew, the 40 carnival jurors were summoned to testify before the commission.

Over the last 25 years, the carnival parade, a huge competition in which dozens of samba "schools" vie for supremacy, has become a big industry, with the city's 13 top schools receiving six-figure sponsorship deals. Exact figures are hard to come by, but media estimates put the cost of the spectacle at more than £50m a year.

Many believe that the influx of so much money has opened the door to growing levels of corruption. On the eve of this year's carnival the vice-president of the Salgueiro samba school was murdered by a gunman using an AK-47 assault rifle. Last October, the president of the Estacio de Sa school was shot dead and bundled into a car boot. According to the police, Flavio Jose Eleoterio was suspected of having links to Rio's illegal gambling mafia, the jogo do bicho, or "animal game".