LOS ANGELES (AP) _ A detective in the O.J. Simpson case was grilled today on misstatements he made to obtain a search warrant for the Simpson estate the day after Nicole Brown Simpson and her friend were slain.

Explaining statements that a judge had earlier described as ``reckless,'' detective Philip Vannatter acknowledged that he wrote in an affidavit that human blood was found on Simpson's Bronco _ although no tests had not been conducted to confirm that.

``That's true. I misstated that. I guess, based on my experience, I believed it was human blood, and I think now, I still think it's human blood. I think it's been proven to be human blood,'' Vannatter said.

Vannatter insisted that his beliefs at the time were warranted by the circumstances since he had just left a bloody crime scene.

Defense attorney Robert Shapiro also questioned Vannatter about another statement on the search warrant affidavit _ that Simpson had taken an unexpected flight to Chicago the night of June 12 when Simpson had actually planned that trip for some time.

``In filling out a search warrant, you indicated to a magistrate, under penalty of perjury, that you were told that O.J. Simpson had left on an unexpected flight to Chicago, did you not?'' Shapiro asked.

``I didn't say I was told that. ... I did write that in the search warrant,'' the detective said. ``I found out later that that information was incorrect. That was based on Arnelle Simpson's response that morning, as well as Kato Kaelin telling me that he had received a phone call after Simpson had left the residence, telling him to alarm the house, that he was going to Chicago on a business trip for Hertz.''

Shapiro asked the questions after Superior Court Judge Lance Ito ruled in the defense's favor, clearing the way for Vannatter to be questioned.

Earlier in the case, the judge sharply criticized Vannatter, stopping just short of calling the detective a liar. Ito noted that the blood was never confirmed to be of human origin and that the trip to Chicago had been long planned. Still the judge upheld the warrant.

``I cannot make a finding that this was merely negligent,'' Ito said at the time, regarding Vannatter's statements on the search warrant affidavit. ``I have to make a finding that this was at least reckless.''

While allowing the defense to ask about the statements on the affidavit, Ito did not allow the defense to tell jurors what he had written criticizing Vannatter.

Prosecutor Marcia Clark had portrayed the misstatements as harmless errors and urged the judge not to waste court time on the subject.

``What we will wind up doing is essentially litigating the validity of the warrant in front of the jury,'' said Clark.

Where the defense earlier tried to portray Detective Mark Fuhrman as a racist rogue cop who may have planted evidence, it has sought to paint Vannatter, a 26-year LAPD veteran, as a sloppy police warhorse out of touch with modern police work.

Meanwhile, the New York Daily News reported today that the defense hopes to reveal the contents of the sealed envelope it introduced last summer during a preliminary hearing.

Shapiro asked Ito during a chambers conference Monday for permission to open the manila envelope in court as early as today, the Daily News reported, citing an unnamed source. It reportedly contains a knife Simpson bought in May.

Shapiro, who has hinted the knife went undetected by police during two searches of Simpson's estate, wants to use the weapon to highlight the defense theme of police incompetence in the investigation, the source said.

The murder weapon has never been found.

On Monday, prosecutors, defense attorneys offered the panelists a rare, up-close look at the former football star.

Escorted by bailiffs and lawyers, Simpson _ appearing embarrassed _ extended a trembling left hand and displayed the middle left finger that the prosecution contends was wounded during the knife attack that killed his ex-wife and her friend. The defense suggested Simpson's knuckle always appears swollen.

Jurors leaned out of their chairs to get a good view. Only one juror looked Simpson in the face; the rest peered only at his hand. None touched him.

With Vannatter's direct testimony finished, prosecutors have now wrapped up the initial questioning of the two lead investigators _ without playing a tape recording of Simpson's half-hour interview with Vannatter and Detective Tom Lange.

The interview took place at police headquarters the day after the June 12 murders of Ms. Simpson and her friend Ronald Goldman.

Legal analysts called the prosecution's move a ``calculated decision'' possibly founded on the belief the recording could make Simpson look sympathetic and remove any incentive for Simpson to testify in the case.

``Maybe they feel they've got a lot of momentum with this police testimony and they want to move right into the forensic evidence,'' said Eleanor Swift, a law professor at the University of California, Berkeley.

``Maybe they didn't want to personalize Simpson,'' she said.

The defense cannot introduce the tape during its case, Swift added, because state law considers out-of-court statements made by defendants to be hearsay. The law provides an exception to the law for prosecutors, she said.