LONDON (AP) _ A court-appointed official said Thursday he has traced and secured about a third of the $1.2 billion in pension fund assets that investigators say were plundered by the late Robert Maxwell.

But Neil Cooper, provisional liquidator for Bishopsgate Investment Management, the main Maxwell company that managed Maxwell pension funds, said another third of the pension funds probably cannot be recovered.

Cooper, an accountant with the firm Robson Rhodes, said he had traced and secured about $412 million of pension fund assets, including both equities and properties.

He said another $378 million in assets were given to third parties as security for loans to other Maxwell group companies. He said he didn't know whether these assets were recoverable.

Another $416 million of the assets appear to have been liquidated and the proceeds transferred to other Maxwell group companies, he said. This money is probably not recoverable, Cooper said.

Cooper said he is still trying to trace the remaining missing $3.5 million.

Robert Maxwell allegedly plundered his companies' pension fund assets and coffers in a desperate effort to try and keep his media empire afloat. He allegedly used the money to pay off debts, cover operating losses and support the share price of Maxwell Communication Corp. PLC.

His publishing empire collapsed after he died at sea on Nov. 5.

Cooper confirmed that he has begun questioning Robert Maxwell's son Kevin, who was ordered by a court to help Cooper trace missing pension fund assets. He also said he was questioning Larry Trachtenberg, an executive at various Maxwell pension fund-related companies.