LOS ANGELES  A hedge fund manager and art collector from New York testified under immunity Tuesday that Anthony Pellicano, the Hollywood private detective accused of wiretapping and racketeering, had once offered to have a movie producer killed for him.

Adam D. Sender, the owner of Exis Capital, a hedge fund that at one point had more than $1 billion in assets, said in Federal District Court here that he had paid Mr. Pellicano about $500,000 to investigate Aaron Russo, a producer and onetime talent manager whose film credits included “Trading Places.” Mr. Russo died of cancer last year.

In 1999, Mr. Sender invested $1.1 million with Mr. Russo. Later, Mr. Sender sued Mr. Russo, accusing him of pocketing the money. Mr. Russo dodged process servers for more than a year, until Mr. Pellicano was brought into the case at the urging of Mr. Sender’s new lawyer, Bert Fields. (Mr. Sender said he paid Mr. Fields’s firm about $300,000, but recovered only $25,000 from Mr. Russo.)

Mr. Sender testified Tuesday that Mr. Pellicano had wiretapped Mr. Russo for a year and had played recordings of Mr. Russo’s intercepted phone calls for him 10 or 15 times. But Mr. Pellicano grew sick of listening to Mr. Russo, Mr. Sender said. And, in a “frightening” moment in the garden of Mr. Sender’s mansion in Bel-Air, he said, Mr. Pellicano suggested killing Mr. Russo.