Yes.

Sounds like it was the judge that committed extortion, and the sergeant was convicted of the judge's crime.

"An Alamenda County judge found the Oakland police sergeant guilty of extortion."

It's a passive construction. Dave's suggestion look right to me.

Doesn't the jury find the defendant guilty, not the judge?

I understood the intended meaning of the sentence the first time through, though I took note of the ambiguity.

Dave Fairchild has posted verbatim what would have been my own clarification.

I agree with Dave and Martina. The sentence is problematic because it's passive; there's also some dangling modifier action going on. Dave's rewrite is good:
"An Alamenda County judge found the Oakland police sergeant guilty of extortion."

P.S. Craig, some trials are "bench trials," which means the case is heard only by a judge, not a jury.

True, there are bench trials (or summary trials as we call them here in Scotland), but they tend to be for civil and lesser offences. I believe extortion is what you call a federal crime, so the right to a jury must be waived by all parties, something which in itself would probably be newsworthy. I'm not convinced the ambiguity alone is sufficient to warrant a rewrite, nor that the students wouldn't have tried that.

Try this one (from space.com today):
"An American astronaut and two Russian cosmonauts are poised to launch to the International Space Station tonight on a Russian rocket." (the astronauts are poised to launch?)

To me, flaw is that the sentence can be interpreted to mean that the sergeant is guilty of extortion, and the extortion was accomplished not through, say, the use of threats, but rather "by an Alameda judge."

The reason they were confounded was because the sentence made perfect sense.

They made the connection between the word "guilty" and "of extortion." Once that is established, it blocked out the thought that the sheriff would use the judge as an instrument of crime.

The ambiguity is there, but it whispers, which makes this a good test for the editor's sensitivity. Catch this one, and you'll catch the more egregious examples.

Another way to rewrite the sentence would be: "The Oakland police sergeant was found guilty by an Alameda County judge of extortion."

Craig: We call a crime "federal" if the U.S. government is prosecuting, which typically means it happened in a post office, on an Indian reservation, in the armed forces, in Washington, or other places where the states have no jurisdiction or the federal government has concurrent jurisdiction.

It's true that "federal case" is slang for "serious matter", but that use shouldn't extend to reports of actual crimes.

"The Oakland police sergeant was found guilty by an Alameda County judge of extortion" sounds to me like the judge only handles extortion cases.

Craig, the sentence refers to a county judge (instead of a federal judge, or U.S. district judge), which indicates that we're talking about a state-level court, not a federal court.

Unless there's a need to put the sergeant first, make it active.

Otherwise, "was proclaimed guilty by a judge in his trial on extortion charges." But, really, I don't think "extortion by judge" is a plausible misreading, and I'd be tempted to let it stand instead.

I don't see a grammatical error: it's passive, so the object of the preposition by is the natural subject of the corresponding active voice sentence.

However, since the verb is irregular and doesn't have a distinguished past participle, it's easy enough to see how a quick reading could lead to a bit of confusion, so I'd change it to active voice.

An Alameda County Superior Court judge found a police sergeant in the Oakland Police Department guilty of extortion.

If you want to keep it in the passive voice, how about:
"The Oakland police sergeant was found guilty, by an Alameda County judge, of extortion"?

I can't see anything at all wrong with the sentence. As Bill Peschel says, you have to try very hard to find a possible ambiguity, and all the proposed variation ssound less natural to me than the original.

I'm a Right-pondian, by the way, which might be relevant in some way.

Grammatically, it is correct. It is passive, but there is nothing wrong with using the passive voice.

There is a remote possibility of ambiguity, but you have to strain to find it. (No sane person would actually find this ambiguous.) And any possibility of ambiguity will disappear when placed in context. (Sentences don't normally exist in isolation.)

If this were in a newspaper, the judge/jury distinction would be valid. In other contexts, like a conversation in a bar, insisting on this distinction would be overly pedantic.

"(the astronauts are poised to launch?)"

Well, if the article was written after they were strapped into their spacecraft . . . :-D

I agree with Dave Wilton. It's passive, which is not a crime in any jurisdiction. And, the article is probably about the sergeant, not the judge, so passive might be the best choice.

Aha!

When thinking about The Ridger's comment that "Unless there's a need to put the sergeant first, make it active," it occurred to me, there are no names!

What sergeant? What judge? Clearly there's been coverage before this, since it went to trial.

The name of the sergeant and maybe that of the judge would already be known. The trial wouldn't be known as the "sergeant trial" but the "Sergeant Slaughter trial."

@ oldfeminist: The sentence is almost certainly not the first sentence in the article (though Googling didn't find it, it was probably something like "Toby Jones, a 20-year police veteran, is facing 20 years in prison.") so "the sergeant" is normal as a second reference. .

I had to work very hard to find a misreading of this sentence, and the misreading that I found doesn't actually make any sense. There would have to a third party who said: "Oakland police sergeant, I find you guilty of extortion by an Alameda county judge." Meaning that the cop is guilty of being the victim of extortion by the judge? Or that the cop is somehow responsible for the judge's act of extortion on some unnamed 4th party to this transaction?

The obvious meaning the sentence is the correct one, and claiming to find it ambiguous is a reach, in my opinion. I find you guilty of excessive pedantry, Mr M.

I assume Oakland has more than one police sergeant. Iy should be An Oakland ...

The Ridger, sure, it is acceptable to use "the sergeant" after first reference. Henry Joseph, it's common to read e.g. "Officer John Doe was found dead in Pasadena." and later, "The Anne Arundel County police sergeant was found in a ditch by the side of the road." The definitive article is okay here because we have already specified one individual.

But the way I read it, this would have to be first reference for "an Alameda county judge."

Why would the judge's name be omitted?

(And why is my captcha "exprefsly spiamplo"?)

So when will it be revealed what's actually wrong with this sentence?

Jonathon, as far as I can see there's nothing really wrong with it. It carries the same clear meaning on initial scan as it does on careful re-reading. Can it be wilfully mis-read to convey something other than its intended meaning? Sure. So can a stop sign.