[giantg2]

It doesn't have to be 1-to-1. You can have different standards for offensive vs defensive use of the information. Showing the DNA matches some relative of a different family could be enough to generate reasonable doubt while still being too weak to generate probable cause to arrest or even search others.

Frankly, they had no probable cause to compell a DNA sample from that guys son. Probable cause is supposed to be that by a preponderance of the evidence that the person has committed the crime. That's clearly not the case as it could be anyone in that family, and with multiple suspects it's not 'more likely than not' that the individual is guilty. Instead the courts allow fishing trips.

[SpicyLemonZest]

I guess that's kinda my point. The Innocence Project should be one of the forefront groups opposing such fishing expeditions. Instead, the article says, the head of the Idaho Innocence Project suggested testing Michael Usry based only on a familial match, because a positive result might have helped get their client Christopher Tapp out of jail. I can't make sense of that, and it certainly doesn't seem consistent with principled caution about DNA forensics.

[giantg2]

And my point is that it's different if a defendant subpoenas you to create reasonable doubt vs the government issuing a warrant without true probable cause.

[SpicyLemonZest]

Is it? Any sort of DNA match falsely implicating you in a murder seems like it would be a big problem, even if it's a defendant looking for reasonable doubt who's seeking it. How comfortable would you be explaining that story to your family, friends, and boss? (Without further reforms, what would stop the government from treating the defendant's match as probable cause and arresting you?)

[giantg2]

Even now, they have to have more than just a DNA match. They have to show evidence of the other elements of the crime. They have issues with evaluating affidavits to ensure they have true probable cause, but that's not an issue with using DNA in this manner.

[gwright]

> Probable cause is supposed to be that by a preponderance of the evidence ..

Really? IANAL, but this sounds like a muddling of what is required for arrest and what is the evidentiary standard for resolving a civil case in the US.

I think realistically the trigger for a search or an arrest is going to be much less than what is necessary to successfully convict in a criminal case or to prevail in a civil case.

[giantg2]

"but this sounds like a muddling of what is required for arrest and what is the evidentiary standard for resolving a civil case in the US."

I remember seeing that the standard for what was reasonable search and seizure in my state was set at preponderance of the evidence. It seems to be in line with other states/fed where you need evidence supporting that the crime has been committed or the object exists in a specific place. This can be, and often is, just an affidavit from the officer(s). Being a one sided process, being more likely than not is satisfied if there isnt an issue with the affidavit like missing element of the crime or unrealiable testimony. The problem comes up when the judges aren't viewing these with an open mind or to the standarss that states set (often these are handled by magistrates that do not hold a law degree nor have passed the bar). Often times the elements of the crimes defined in statue haven't even been claimed to have been met in the affidavit.

As an example, there might be someone operating a still at their residence. Just the sight of a still does not provide probable cause (only reasonable suspicion, and even that could be arguable). For probable cause to be met, you would have to prove that it was used for alcohol and that the person didn't have a fuel distillation permit or was selling it, etc (and probably one or two other small things in the statute). This is specific to my state. Other states may have more stringent rules about even owning a still.

"I think realistically the trigger for a search or an arrest is going to be much less than what is necessary to successfully convict in a criminal case or to prevail in a civil case."

It is less than the standard for conviction. All it needs is to show the elements of the crime have been claimed to have been met in the affidavit. Although they aren't even meeting this standard in every case. Or in some cases the officers have lied or made mistakes.

It's not exactly the same as a civil case since the warrant process is ex parte and does not need to consider defenses to the charge. It's just the same level of proof but applied to one-sided testimony. For example, you might have shot someone in self defense and the witnesses all agree it was self defense. They can still charge you (in most states) and make you prove that defense in court. You could get into some malicious prosecution stuff here, but according to probable cause you have satisfied all the elements of the crime and can be charged. Proving your defense then happens at the trial.

IANAL either, but have some criminal justice background. These are just what I have seen as it applies in my state.