Marcelo Cattaneo, a key witness in the IBM/Banco Nacion scandal Argentina's most high-profile case of alleged corporate corruption has been found dead.

Mr Cattaneo's body was found hanging from an abandoned broadcasting aerial tower on Buenos Aires wasteland on Sunday. He had disappeared four days earlier. Officials yesterday said the death appeared to be suicide, but they were not ruling out other possibilities.

The death is likely to prove acutely embarrassing for President Carlos Menem's government as it enters its final year. It follows a series of deaths of people allegedly involved in scandals surrounding the government.

Adolfo Bagnasco, a federal judge, has accused IBM's wholly-owned Argentine subsidiary of agreeing to pay a $37 million (£24.2 million) bribe to win a $249 million contract to computerise the branches of state-owned Banco Nacion, the country's biggest bank, in 1994. Some $21 million in bribes was allegedly paid over before the affair came to light.

Judge Bagnasco has issued inter national arrest warrants for four serving or former IBM executives for questioning. IBM has said it is willing for them to testify in the US under the terms of a bilateral legal accord, but not in Argentina.

The Banco Nacion scandal has proved a public relations disaster in the country for IBM.

IBM headquarters in the US has consistently denied it knew the details of the Argentine contract.

IBM could not be reached for comment yesterday.