This is serious.

Perhaps not serious enough to derail the prosecution of Demeatrius Montgomery — Judge Forrest Bridges will have to decide that question. But almost certainly serious enough to lay grounds for an appeal of a murder conviction.

As we were the first to report last week, Det. Arvin Fant has had evidence under his watch go missing before. Yesterday we learned that Fant did indeed destroy his notes in the Montgomery case and is under investigation by CMPD for his conduct. The details:

In another twist, Assistant District Attorney Marsha Goodenow was called to the stand to recount how she learned what Fant had done.

In late July, she said, Montgomery’s attorneys asked her about inconsistencies in Fant’s notes.

She met with Fant and his superiors. At one meeting, she said, Fant seemed defensive.

He phoned her the next day, saying he wanted to talk. She expected an apology for his previous demeanor. Instead, he revealed more details about discarding notes.

“At that point, I didn’t ask him a single question. I knew I was in a predicament. I did not want to be called as a witness in this case,” she said. “And I told him (defense attorneys) would be coming after him.”

Fant is under investigation. Prosecutors said he admitted doing similar things with notes in other cases. Police Chief Rodney Monroe, who attended the trial, said he wants to wait for a ruling on the motion before commenting on Fant.

No kidding, Chief. If Judge Bridges decides he has no choice but to dismiss the case, I bet you’ll have a comment or two on Det. Fant.

But answer this now: How is it that a guy with a proven track record of being sloppy with evidence was anywhere near such a high-profile case? Shouldn’t someone at least have been looking over his shoulder every step of the way to make sure something like this didn’t happen?

And how would you like to be Forrest Bridges right now? If the prosecution cannot convince you that Fant’s missing notes simply duplicated existing evidence — and I’m not certain how they do that other having everyone from Fant on up swear up and down that is the case — and did not contain a shred of exculpatory evidence, do you have the guts to dismiss the case?

A dismissal would cause the city to explode and tear the hearts out of the officers’ families. I don’t think a dismissal likely, but the fact that we even have to contemplate such a thing points to serious issues within CMPD.

Bonus Observation: In a way Judge Bridges is free to let the trial proceed precisely because he knows any conviction will be appealed any way. So he doesn’t have to worry about ruling “right” or “wrong” on the dismissal motion from an ego point of view.