ROME (Reuters) - Late tenor Luciano Pavarotti "knew exactly what he was doing" when he signed a will leaving his assets in the United States to his second wife, Pavarotti's manager said on Thursday.

A notary involved with the will told a magazine earlier this month that he was "unhappy about some points" of the document but was prevented by lawyers from making any amendment.

That prompted media speculation that the will was imposed on Pavarotti, who died last month at 71 after battling pancreatic cancer, and that the tenor was too sick to understand what he was signing.

"Mischief makers are painting him as a vulnerable man who was coerced," Terri Robson, Pavarotti's manager, told Reuters in an e-mail.

"Pavarotti was a highly intelligent man and knew exactly what he was doing when he initiated this will over a period of time in collaboration with his Italian lawyer and his U.S. lawyer of many years," she said.

"To suggest otherwise is insulting and patronising".

An Italian magistrate this week said he was looking into the press reports with a view to possibly initiating a probe.

The will, which dates from July, makes Pavarotti's second wife, Nicoletta Mantovani, the sole beneficiary of a trust fund controlling his American assets, which include property in New York and are said to be worth 15 million euros.

Since Pavarotti's death, the Italian media has been awash with reports of a battle over the inheritance between Mantovani and Pavarotti's three daughters from his first marriage.

Mantovani has a four-year-old daughter by Pavarotti.

Three wills have emerged. The first from December 2006 is said to have been handwritten by Pavarotti, and according to media reports left most of his estate to his four daughters.

A second, this June, split Pavarotti's assets between his daughters and Mantovani. The third document is the one relating to the U.S. properties.

Robson said however that "the so-called handwritten note was not, in reality, less favourable to Mantovani" than the one published subsequently.