BRASILIA (Reuters) - Brazilian police and federal prosecutors on Thursday (Jan 26) issued a detention order against former billionaire Eike Batista and eight others amid a series of raids and searches related to the country's worst bribery and graft probe.

A police spokesperson told Reuters the measures were part of"Operation Car Wash", an investigation into a US$100 million money laundering ring. The searches were taking place in Rio de Janeiro, the police said in a statement.

The news channel GloboNews reported that police had raided Batista's home in an upscale neighborhood of Rio but failed to find him there.

It cited unnamed lawyers representing him as saying he was travelling and planned to turn himself in on his return.

Efforts to contact Batista's lawyers for comment were unsuccessful.

Once Brazil's richest man, with a fortune calculated at about US$35 billion less than five years ago, Batista has been hard hit by the crash in Brazil's decade-long commodities boom, which led to the collapse of his Grupo EBX - a conglomerate of mining, energy, shipbuilding and logistics companies.

The "Car Wash" scandal has centred around the cozy relationship between members of the former Workers Party administration and some of Brazil's most prominent businessmen over contracts at Petróleo Brasileiro SA and other state firms.

The investigation has undermined investors' trust in Brazil's companies just as its longest and harshest recession bites deep.

More than 100 people, many from companies built up as national champions, and including Brazil's most powerful building tycoon, Marcelo Bahia Odebrecht, have been convicted of corruption linked to kickback schemes, racketeering and money-laundering.