You wonder how anyone gets convicted in California unless they’re caught holding the murder weapon standing over the body.

Jeffrey Welbaum was selected last year as an alternate juror in the Michael Jackson child molestation trial. I used to watch him from the public seating; he was young, large (which helped for my eyesight) and with an easy face to read. You could tell he didn’t believe a word of any prosecution witness.

Turns out he had a good reason. His mother-in-law, Patti, had worked for Jackson and his family for about five years. She was actually employed at the ranch when the Arvizo family used to visit. She was on the defense witness list but had a different last name, so no one paid much attention, if they knew at all.

Ironically, the Santa Barbara News Press reported this little fact in February 2004 during jury selection, but either it was a slow day or no one noticed. It was never mentioned again that Judge Rodney Melville, according to the paper, allowed this, and so did the lawyers involved.

Welbaum apparently told the court during his voir dire hearing that he would hold his mother-in-law to the same standards as any other witness if she took the stand.

Luckily, she never had to. And sadly, Patti Henkins died suddenly just last month from a heart attack at age 59.

But imagine if she’d been called as a witness. I mean, we knew sitting there that we were in a kangaroo court, but this is too much. Santa Maria is not such a small town that this could happen by accident. It’s no Mayberry. Frankly, if I were a resident of the county and read this now, I’d demand the entire district attorney’s office be fired.

Henkins’ daughter, Sherri Welbaum, is the wife of Jeffrey Welbaum, who last week put his notebooks from the trial up on eBay for auction.

After getting few bites, he took them down on Sunday morning. Sherri told me they did it as a lark, and that their 17-year-old daughter had been against the whole thing. “It’s history,” she said.

Here’s something funny: one of the two bidders who got the notebooks up to $701 was Vinnie Amen, one of the five unnamed co-conspirators in the trial who did not appear but whose name was mentioned often.

Amen preposterously alleged the Arvizo family held them against their will at Neverland and elsewhere, forcing them to eat out, shop for clothes and get full body waxes and beauty treatments. The jury did not find the family credible.

Neither did Patti Henkins. Sherri Welbaum told me her mother had been present when the Arvizos visited Neverland, and that they were terrible kids.

“They were rough,” Sherri said.

She also said her mother never believed all the stories about Jackson and other kids. She also dreaded being called as a witness.

I’ll bet she did. It might have been a first in California history. It was just enough that Jeffrey Welbaum came to court equipped with a formed point of view and insider in the case.

Are there more stories like this among California celebrity cases? I don’t know, but I do know that O.J. Simpson lives a free life in Florida, and that I recently saw Robert Blake at a rib joint in Malibu. They were each acquitted of killing their wives.