Santa Maria, Calif. ? Set aside Michael Jackson’s wealth and celebrity, and his trial could be a textbook lesson – a study in the pitfalls prosecutors face in trying to make child-molestation charges stick.

The credibility of the accuser and his family came under withering attack. Some of the children’s testimony was inconsistent and muddled. And there was no DNA evidence, no smoking gun.

“Some prosecutors don’t want to touch these cases with a 10-foot pole because they are so difficult,” said Victor Vieth, director of child abuse centers at the American Prosecutors Research Institute in Alexandria, Va.

It’s unclear how many of the thousands of molestation cases filed each year nationally end with jurors returning guilty verdicts; rough estimates run between 50 and 75 percent. In California, more than 3,420 defendants were found guilty of various sex crimes against minors in 2003, a conviction rate above 74 percent, according to the state Department of Justice.

However, the rate generally is lower in cases that depend heavily on the victim’s word, Vieth said.

That’s partly because prosecutors not only have to present a case against the alleged abuser, they must protect the accuser against defense counterattacks.

“The first question the jury is going to ask is ‘Why would this child make up these allegations?”‘ said Leonard Levine, a prominent Los Angeles defense lawyer who has handled close to 100 child molestation cases. “And if you can give them a reason as a defense attorney, you’re halfway there.”

Jackson’s prosecutor, Santa Barbara County Dist. Atty. Tom Sneddon, said molestation cases are hard to prove because they often leave no physical evidence.

“They’re far more difficult than murder cases. Murder cases you usually have a gun or a knife or blood or fingerprints or something,” Sneddon said in an interview. “I’ve tried cases where they never found the body. I’ve had two of those cases. And those cases were much easier to try than some of the child molestation cases I’ve had.”

The Jackson case had factors that complicated the prosecutors’ job, said Sneddon’s deputy, Ron Zonen.

“This case became more difficult because we were dealing with a 13-year-old boy from East L.A. who was rather unsophisticated, who was against not just a celebrity but an international superstar,” Zonen said.

The deep pockets that come with celebrity tipped the scales even more. Jackson was able to hire a top defense lawyer, Thomas Mesereau Jr., who dug up alleged scams involving the accuser’s family to portray them as career con artists who had been after the singer’s money.

Prosecutors were able to capitalize on an unusual California law to introduce old – and uncharged – molestation allegations against Jackson, but those accusations couldn’t eclipse doubts about the family’s credibility.

Sneddon and his team also couldn’t produce any biological or medical evidence of abuse. Only 20 percent of cases involve such physical evidence, according to David Finkelhor, director of the Crimes against Children Research Center at the University of New Hampshire.

As a result, many prosecutors are forced to build cases on testimony alone, a strategy made more risky when the witnesses are children, who can be rattled and have trouble recalling key details in court.

Concerns about flawed child testimony grew in the 1980s and ’90s, after molestation cases such as the McMartin Preschool case in Los Angeles County, the Little Rascals case in North Carolina and the Margaret Kelly Michaels case in New Jersey fell apart.

Interviewing techniques have since improved, and some jurors have become more forgiving of child testimony partly because of the Catholic church sex abuse scandal and child abduction and murders that have drawn national attention, lawyers said.

However, none of that helped when the brother of Jackson’s accuser testified and gave an account of the alleged molestation that differed from statements he made to sheriff’s investigators. And the accuser himself initially couldn’t recall telling a grand jury that Jackson said it was “natural” when the singer appeared nude in front of him and his brother.

“As a prosecutor, once you lose the credibility of your witness, you’re done,” said Larry Hardoon, former lead prosecutor in Massachusetts’ infamous Fells Acres sex abuse case, which produced convictions but led to the discrediting of the interview techniques used by investigators. “It’s the end of the story.”