Law-abiding citizens relish the concept of justice. It helps them face the evils of the world day in and day out.

But America’s judicial system — as good as it is — doesn’t always produce popular results — often just the knowledge that someone is in jail for the crime.

But maybe the defendant simply wasn’t guilty. Maybe law enforcement mishandled the case. Maybe the prosecution failed or the jury.

Any number of things can affect the outcome of a courtroom trial in favor of the defendant or against him.

But no one — most of all the police investigators themselves — wants to believe that a guilty person walks free because of something the police did or didn’t do.

It’s understandable that the Natchez police chief and his team are frustrated and upset that a guilty verdict didn’t come in a recent case involving a bank robbery and shooting of a law enforcement officer that they viewed as open and shut.

The defense attorney — as you’d expect — pointed a finger at the NPD throughout the case, claiming they simply hadn’t done their jobs.

Maybe she was right. Maybe she wasn’t.

Either way, Chief Danny White says he’s looking at ways to ensure such accusations have absolutely no foundation next time.

NPD apparently has no written policy governing what evidence is sent for crime lab review and what is not. White wants to fix that, and clearly that should be priority No. 1 on the matter.

But one disappointing case shouldn’t swing the NPD’s investigative procedures 100 percent in the other direction and require crime lab testing on every piece of evidence in every case, as White suggests the department will now do.

Forensic reviews are expensive and sometimes unnecessary. Even having them may not win the case.

Instead, writing a policy that outlines the steps for a case-by-case review of evidence is likely the best option.