I've posted a link below to a Washington Post article about a man who was charged but acquitted of robbery, yet nonetheless still went to prison for violating his probation. There are some reported facts in the article that I find a little perplexing, which I will explain, but first it is important to understand how new allegations can affect probation.
When a person pleads guilty to a crime, it is common for the court to place the defendant on probation rather than sending them to prison. Probation will often have a variety of conditions, which if violated can result in the probation being revoked and the person sent to prison. Conditions often include supervision by a probation officer, reporting directives, avoiding felons, reporting new arrests, reporting employment or residency changes, and of course not committing new crimes. If the probation officer believes the probationer has violated one of their conditions of probation, a report is filed and the court will hold a hearing to determine if they in fact violation their probation.
Probation violations, unlike new criminal charges, have a lower standard of proof. In other words, a judge needs less evidence and does not need to be as convinced of a violation as does a jury in a criminal trial. Juries must find that the defendant is guilty beyond a reasonable doubt before convicting someone, but a judge only needs to find that the defendant more likely than not violated probation, what's called the "preponderance of the evidence" standard. A jury should never convict simply because it believes someone probably committed a crime, even if they have reasonable doubts about guilt, but this is the standard that a judge uses. This means that a person could be charged with a crime, be found not guilty, and yet still have their probation revoked because of the same allegations. In these cases, with both new criminal liability and a pending probation violation, we typically try the case to a jury in front of the same judge hearing the probation violation, so that the evidence does not need to be presented a second time before a different judge.
The peculiar part of the story below is not that the defendant's probation was revoked following an acquittal at trial, but because the condition that he apparently violated was simply being arrested. I have never seen an arrest itself being the basis for a violation, especially as that is not a willful act and the arrested probationer may well be completely innocent of any wrongdoing. Failing to report the arrest can violate probation, and committing a crime that caused the arrest are a violations, but simply getting arrested, in my 17 years of practice, has never been a violation of probation. It makes me wonder if either the reporting in this story is accurate, or more worrisome, what exactly is going on in Georgia.