LOS ANGELES (AP) _ O.J. Simpson and his lawyers, aware within hours that he was a prime suspect in a double murder, quickly focused on his quirky houseguest Brian ``Kato'' Kaelin as the man who might clear him, Kaelin told jurors Wednesday.

The shaggy-haired witness said Simpson and his lawyers tracked him down at a friend's house the day after the knife slayings of Nicole Brown Simpson and Ronald Goldman, and Simpson himself got on the phone.

``O.J. said, `Kato, you know I was in the house,''' Kaelin recalled. But he said he told Simpson then what he said on the witness stand _ that he never saw Simpson enter his house after they returned from a trip to McDonald's the night of the killings.

Kaelin, a prosecution witness whose prickly relationship with Deputy District Attorney Marcia Clark was evident in court, described an evening with Simpson that provides a possible timeline for murder. He also told jurors about a previously undisclosed quarrel Simpson had with his ex-wife hours before she was slain.

But Kaelin rebuffed Clark's efforts to portray Simpson as angry and shouting about his ex-wife after their daughter's dance recital. And he said that although Simpson seemed ``in a hurry'' to make a flight to Chicago he wasn't ``frazzled,'' as Clark implied.

Simpson appeared elated through much of Kaelin's testimony and at day's end he turned to friends in the courtroom and gave a thumbs-up sign.

Kaelin said Simpson and his then-lawyer, Howard Weitzman, tracked him to a friend's home June 13, the day after the murders, after he had given interviews to police.

``What did they say?'' Clark asked.

``They said to tell the truth,'' Kaelin said.

In a second phone call, he said, they discussed ``the night of strange things'' and Kaelin's report of hearing thumps against his guestroom wall, noises that later led a detective to a glove stained with blood from Simpson and the victims.

When he encountered Simpson at home late June 13, Kaelin said, the defendant was surrounded by a throng of friends and family. By then, he already had been briefly handcuffed and questioned at police headquarters.

``He was asking me, did I see him go back in the house, and I didn't,'' Kaelin said.

Clark at times struggled to pry answers out of Kaelin, who although more subdued than when he first took the stand Tuesday still displayed flashes of impish humor.

When Clark asked if Simpson was excited when Kaelin invited himself to go get a hamburger the night of the murders, Kaelin paused, then said, ``Wouldn't you?''

Simpson and the jurors laughed aloud, and even the judge smiled. During most of his testimony, however, jurors listened intently, and some took notes. Kaelin took frequent gulps of water from a red plastic cup at the witness stand.

Clark implied that Kaelin's acting career has skyrocketed since the murders, and the witness acknowledged he's been working more than he has in the last 10 years.

She asked Kaelin if he considers himself Simpson's friend.

``I am still a friend,'' he said. ``I know my job is to be 100 percent honest and that's something I'm going to do.''

Kaelin told jurors Simpson confided in him after returning from his daughter Sydney's dance recital June 12, 1994.

``He said Sydney was great at the recital,'' Kaelin recalled, ``that Nicole was there and some friends.''

``What, if anything, did he say about Nicole?'' Clark asked.

``He wanted to talk to Sydney, and I don't think _ Nicole wasn't going to give him time to talk to Sydney, and I think they (Ms. Simpson and her children) went off somewhere,'' he said.

Clark asked Kaelin if Simpson was allowed to spend any time with his daughter and the witness said, ``A short time.''

Kaelin, 36, a would-be actor with a thatch of long, blond hair, was living in Simpson's guest house rent-free in the summer of 1994. His testimony is crucial because he was the last person to see Simpson before the time period when prosecutors contend his ex-wife and her friend were murdered and one of the very few to see Simpson shortly after that hour.

Kaelin's report of thumps on a wall at Simpson's estate about 10:40 p.m. was seized upon by police and prosecutors as a keystone of their circumstantial case. Authorities have found no murder weapon, no eyewitnesses and no bloody clothes. But they say the timeline provided by Kaelin points to Simpson as the killer.

On Wednesday, Kaelin pounded his fist on the witness stand to demonstrate the three loud thumps he first thought signaled an earthquake the night of the murders.

Prosecutors contend Simpson went to his ex-wife's condominium, committed murder, returned home and dropped a bloody glove behind Kaelin's room before rushing to meet a limousine that was waiting to take him to the airport about 11 p.m.

Simpson went to Chicago for a planned business trip and returned the next morning after being notified of his ex-wife's murder.

Kaelin's account was almost identical to the one he gave at last summer's preliminary hearing, which resulted in Simpson being held for trial.

Kaelin said he encountered Simpson throughout June 12, first in the afternoon when he heard him talking on the phone with girlfriend Paula Barbieri and later to Kaelin's friend, Playboy model Tracy Adell. The latter conversation, he said, concerned business.

Simpson went to his daughter's recital in the late afternoon and talked with Kaelin when he returned. He said he had to pack for a trip to Chicago and was displeased that he was booked on a ``red-eye'' flight.

Late in the evening, Kaelin said, Simpson came to his room and said he needed change to pay a skycap because he only had $100 bills. Kaelin gave him $20. He told his house guest he was going out for a hamburger, and Kaelin said he asked, ``Can I go?''

Together, they left for McDonald's in Simpson's Bentley about 9:10 p.m. Simpson wore a dark sweatsuit and looked tired, Kaelin said.

``There was some conversation about the flight and the airline, being tired. At one point I said, `You ought to take a nap. You look tired.''

``What did he say?'' Clark asked.

``He probably wouldn't have time to.''

Kaelin said Simpson ordered their food at the drive-up window and ate his hamburger while driving the car.

``He finished pretty fast, ate and drove,'' said Kaelin, who added that he nibbled a few french fries but took his hamburger home.

Back at Simpson's estate, Kaelin said, he last saw Simpson standing at the driver's door of the Bentley. He said he returned to his room and made a phone call.

Kaelin's telephone bill, enlarged for jurors, recorded the call at 9:37 p.m.

Kaelin said he made another call at 10:10 p.m., to friend Rachel Ferrara, and during that call, ``I heard a thumping noise.'' He estimated the time at 10:40 to 10:45 p.m. and said he thought at first there had been an earthquake, then suspected a prowler.

But when he went outside with a small flashlight, he said he saw nothing. Twice, he said, he returned to the pathway where the detective later found the glove that matched one at the murder scene. Kaelin said he never walked back to the area where the glove was found.

Minutes later, he said, he spotted a limousine and driver waiting for Simpson and let the driver enter the gate. He said he helped load Simpson's baggage, but when he leaned down to pick up a dark knapsack, Simpson said, ``I'll get it.''

Prosecutors have never explained why the knapsack is important, but Clark told the jury in her opening statement, ``That small, dark bag was never seen again.''