Legal Question in Criminal Law in California

I hate to sound like a cliche, but the answer is it depends.

The general statute that governs is Penal Code section 1098. "When two or more defendants are jointly charged with any public offense, whether felony or misdemeanor, they must be tried jointly, unless the court order separate trials. In ordering separate trials, the court in its discretion may order a separate trial as to one or more defendants, and a joint trial as to the others, or may order any number of the defendants to be tried at one trial, and any number of the others at different trials, or may order a separate trial for each defendant; provided, that where two or more persons can be jointly tried, the fact that separate accusatory pleadings were filed shall not prevent their joint trial."

Separating the trials is done with a motion, and those motions are dependent on factual issues and legal issues that are not in front of me. Your lawyer may have tried a motion, or may not know, or may even have strategical reasons for not doing such a motion.

You should really to talk to your attorney. He would know better about the option to sever. Prosecutors like one trial out of one episode. There are reasons for separate trials but this goes to strategy, the parties, and who has evidence against who etc...

Probably. Co-defendants' cases can be separated in some circumstances but not in others. You haven't told us anything about your case, so I can't form an opinion about whether you can do this. But your lawyer can form such an opinion, and he has. That opinion is probably correct.

Note that, even if you can get a separate trial, there might be very good reasons not to.

You can get a second opinion, but you will need to consult directly with a lawyer and reveal a lot more about your case than you can -- or should -- in a public forum like this one.

Good luck.

While I agree with the above comments you should know that severances are rarely granted and the presumption is that people who are alleged to have committed a crime together are tried together.