When you’re innocent of a violent crime, you probably think that careful investigation by the authorities will likely reveal the truth of the matter and you’ll never go to trial. The terrifying reality, however, is that your odds of being arrested and convicted — even when you’re innocent — rise dramatically as soon as the police look your way.

Blame confirmation bias for the problem. Confirmation bias is what happens when evidence is consistently interpreted in a way that reinforces the presupposed notions that investigators have of a suspect’s guilt or innocence.

Criminologists at Texas State University looked at 50 wrongful convictions and determined that confirmation bias played a big role in the way that innocent people end up in prison — or even on death row. Combined with the pressure from higher-ups to solve a troubling case quickly and gain a conviction, the authorities tend to develop what researchers refer to as nothing short of “tunnel vision.”

In other words, the police zero in on a suspect and then interpret anything ambiguous in the light least favorable to the defendant. If some piece of evidence doesn’t fit the scenario they have in their minds, it may simply be ignored.

That tunnel vision can lead to aggressive interrogation tactics that are not — as many people believe — designed to get to the truth of a matter but solely intended to break down a suspect’s defenses and get them to confess (whether they’re guilty or not).

Once you’ve been arrested for a violent crime, make no mistake: The police believe that they already know the truth and they aren’t interested in anything that contradicts that view. The smart move is almost always to reach out to an experienced defense attorney for assistance as quickly as possible.