LOS ANGELES (AP) _ O.J. Simpson spoke on the telephone with his ex-wife the day she was murdered, and a witness who was with Simpson described him as upset, a prosecutor said in court records released today.

Deputy District Attorney Marcia Clark, during a sidebar discussion at Simpson's murder trial Monday, revealed that cellular phone records indicate a call was made from Simpson's phone to Nicole Brown Simpson's house at 2:18 p.m. on June 12, while Simpson was at the Riviera Country Club. Simpson golfed and played gin rummy there that day.

A woman at the country club will be called to testify about the four-minute phone call, Clark said, according to a transcript of the conversation.

``We have a witness who observed him on the cell phone angry, yelling,'' Clark told the judge and defense attorneys outside the jury's presence.

Clark said the witness, who wasn't identified, was unclear on the time she saw Simpson speaking on the phone, but phone records show that only one call was made that afternoon. All other calls were made at night, Clark said.

``So there was only one call it could have been,'' Clark said.

Monday's sidebar was prompted by a question about the call that Clark asked Simpson's former houseguest, Brian ``Kato'' Kaelin, who was on the stand for a fifth day today.

As today's session got under way, Clark pressed Kaelin _ decreed a ``hostile'' witness to the prosecution Monday _ about whether he stood to reap financial rewards from the case. She asked him how much money he had made since June 12 _ $60,000, Kaelin said _ and whether he was writing a book. Kaelin said he wasn't at present but would not rule it out.

Winding up his testimony, Kaelin told defense attorney Robert Shapiro, ``I would not lie.''

``For any amount of money?'' Shapiro asked.

``For any amount of money,'' Kaelin said.

Kaelin was excused, although the judge said he was subject to recall. Later, in a brief, hectic news conference, Kaelin said the Simpson case has been an ordeal.

``Life is precious, and I realize that. I'm much more emotional now,'' said Kaelin, who refused to answer a litany of questions about the facts of the case.

Rachel Ferrara, a friend of Kaelin's who was talking with him on the telephone the night of the slayings, was on the stand briefly after him. She corroborated his account of hearing bumps on his guesthouse wall at about 10:40 p.m. that night. Ferrara said Kaelin told her about the noises, fearing it was an earthquake.

Prosecutors then called limousine driver Allan Park, who drove Simpson to the airport the night of the killings, to the stand.

Monday was the first time the prosecution suggested that Simpson had any contact with his ex-wife on the day of her death other than an evening recital for Simpson's daughter Sydney. Simpson and his ex-wife left that event separately.

Shapiro didn't deny Simpson spoke to his ex-wife, but suggested he could have been speaking to Ms. Simpson about ticket and seating arrangements for the recital.

Shapiro objected to allowing the prosecution to question Kaelin about the call, but the judge allowed it. Kaelin testified that Simpson never mentioned the phone call that day.

Also Monday, Clark pressed Kaelin about Simpson's relationship with his two children, who lived with his ex-wife.

During a sidebar, Clark revealed that Ms. Simpson's diary indicated that Simpson repeatedly failed to pick up his children for scheduled visits.

``There was at least every other week that he was missing his visits with the children, and that he would schedule things, schedule dinners to take them to and never show up, schedule weekends to have them and never show up, or bring them back earlier than scheduled,'' Clark said.

Ito questioned whether Simpson's relationship with the children was relevant, adding, ``I don't think there is any question that the defendant loves his children.''

``Really?'' Clark asked. ``We don't see eye to eye on that one at all.''

``Well, aren't we going far afield?'' Ito asked. ``Loving the children is one thing. Killing the mom is something else.''

``I don't think so,'' Clark said.

Simpson is on trial for the slayings of Ms. Simpson and her friend, Ronald Goldman, outside her Brentwood condominium.

At one point Monday, in front of the jury, Clark asked to have Kaelin designated a hostile witness. That designation, approved by Ito at a bench conference out of the jury's hearing, allowed her to cross-examine her own witness, which legal analysts say Clark had basically been doing anyway.

Law professor Erwin Chemerinsky of the University of Southern California said Clark may have been trying to send jurors a message that, since Kaelin is sympathetic to Simpson, they should put a lot of weight on any incriminating evidence he offers.

Clark put Kaelin on the stand last week to sketch out a critical time period between a hamburger run and a limousine pickup. That is when prosecutors claim that Simpson did the murders.

But after eliciting what the prosecution needed, Clark turned on Kaelin, suggesting he was shading his answers to make his no-rent landlord look better _ particularly when describing Simpson's demeanor the day of the murders and details of Simpson's rocky relationship with Ms. Simpson.

Meanwhile, legal papers filed by a prosecution DNA lawyer Monday indicated that the vitriol being exchanged by opposing lawyers may be a precursor to an even nastier battle.

Deputy District Attorney Rockne Harmon threatened to launch a personal attack on a Nobel Prize-winning scientist if the defense calls him as a witness. He labeled as ``irrelevant'' the opinions of Dr. Kary Mullis, who received the Nobel for chemistry for conceiving the polymerase chain reaction process used in testing many DNA samples.

The defense has suggested that Mullis will say he has reservations about the forensic applications of DNA testing in criminal cases.

Harmon said the prosecution would paint Mullis as a ``longtime drug (LSD) user-abuser, a fact which he freely admits'' and would show that he believes the HIV virus does not cause AIDS.