Husband and wife married ~15 years/ She develops habit and moves out, divorce proceedings initiated. She signs HIS name to old checks (drawn on a still valid account) at HEB, which bounce. He makes police report of forgery when we make him aware because they were filed as hot checks in our office. Detective investigates and has wife passing the check on video. Detective refuses the case on the basis that the funds in the account were community property.
As near as I can determine, she did forge his signature and intended to harm him. Anybody believe differently?

Yes, it sounds like you have a forgery. The community property issue is irrelevant - that would only matter if you alleged theft. Not that it really matters, but since the checks were returned, there was probably not any "community property" in the account. I think you also have an IBC case, but the felony would be easier to prosecute.

I agree, forgery is making an act that purports to be the act of another without that person's consent--it doesn't matter whether the person is a spouse or not. The only defense argument that would make sense here is that she did not intend to harm or defraud anyone because the money in the account was community property. The problem with that argument is that if she knew the account was NSF, then she intended to defraud the merchant and possibly harm her husband my putting him behind the 8-ball for the bad check.

I wonder if she is a signatory on the account. If she could have signed the check with her own name, but used her husband's instead, that might be good evidence for you of intent to defraud.