Santa Maria, Calif. ? Michael Jackson — dressed in white and accompanied by members of his family — returned to court Monday to watch a showdown over key evidence with the prosecutor who has pursued the singer for years on child molestation charges.

In a tense, packed courtroom, Jackson defense attorney Thomas Mesereau Jr. took the offensive, questioning Santa Barbara County Dist. Atty. Tom Sneddon for two hours over a November 2003 search of the office of a private investigator hired by Jackson’s former attorney.

The exchanges were testy at times. At one point, Sneddon said he didn’t know how the defense wanted him to answer a question. “Truthfully, hopefully,” Mesereau replied.

When Sneddon said he could not give a yes or no answer, Judge Rodney Melville promptly warned him: “Mr. Sneddon, I’m going to ask you not to spar with the attorney.”

Mesereau, arguing Sneddon violated Jackson’s attorney-client privilege by searching the investigator’s office, is seeking to have evidence gathered during that search excluded from his trial on child molestation charges.

If successful, the move could undermine the prosecution case. It is one of the issues that must be settled before Jackson’s scheduled Jan. 31 trial.

The hearing is scheduled to last several more days. The judge is not expected to issue an immediate ruling.

Jackson, 45, is charged with committing a lewd act upon a child, administering an intoxicating agent and conspiring to commit child abduction, false imprisonment and extortion. He has pleaded not guilty and is free on $3 million bail.

Sneddon refused to acknowledge he even suspected a professional relationship between former Jackson attorney Mark Geragos and the investigator, Bradley Miller — even though the prosecutor acknowledged seeing a large file of letters that carried the names of both men.

Michael Jackson, center, with sisters LaToya Jackson, left, and Janet Jackson, leave the courthouse in Santa Maria, Calif. Several members of Jackson's family attended the pretrial hearing about molestation charges against the pop star.

“Are you saying you didn’t know that Mr. Miller was working for Mark Geragos at the time?” asked Mesereau.

“I am 100 percent certain of that,” Sneddon said.

The prosecutor admitted telling defense attorneys in July he knew Miller worked for Geragos but testified he retracted the statement the next day. “It was a mistake,” he said.

The singer, who wore a gold brocade armband over a white suit, sat perfectly still and stared at the prosecutor. The rest of the Jackson family, including five siblings dressed in white, also sat impassively. They left the courthouse, with a police escort, after Sneddon’s testimony.