We spoke with the U.S. Attorney's office in Springfield who gave us the details on how this happened.
But aside from the circumstances in this case,others tell us people can often slip through the cracks.
We talked with one man, Brian Gaines, who could have been one of them.
Gaines said "my suspicion is that it's not extremely uncommon that people who don't have the right to vote do vote, because it's not enforced much."
He's a political science professor at the U of I.
He's a legal voter, but he says there was a time he could have been an illegal voter.
He said "when I was still a Canadian citizen...I'm now naturalized...getting my driver's license...I was asked when I got my license, if I'd like to register to vote. I said 'no, I'm a Canadian.' She said, 'Oh. Would you like to register or not?' I think the lack of citizenship requirements is pretty wide spread."
Valencia-Sandoval is accused of illegally voting in three separate elections.
A federal affidavit says he did that by using the alias Ramiro G Vasquez...a stolen identity that allowed him to live in Illinois for the past 11 years and voice his vote just this past November.
But Gaines told us this might not be where he lands in the most trouble.
"Even a case like this may not lead to a conviction of voter fraud," said Gaines. "They have a lot of charges against them. It could be that charge is dropped. So someone who is counting the convictions and says "look there isn't much vote fraud" might be reaching the wrong conclusion. But it doesn't mean it's widespread. It just means it's hard to know."
Immigration advocates, like Ricardo Diaz, say an illegal voter might not be a big deal for the election result...but it's a big deal for everything he stands for.
"Every time there is a crime committed, and we can read between the lines that it is an immigrant, it hurts," said Diaz. "It hurts because so much work, because the work of so many just peaceful people is stained."
He said most people coming into the country work hard to gain citizenship, and all the rights that come with it.
But for people like this, he feels like not much can be done.
"At the same time we have no way to control because they're not the ones who are going to come and get the training, and learn what is right and what is not. They're consciously doing wrong," said Diaz.
If Valencia Sandoval is convicted of making a false claim of citizenship to vote, he could face up to five years in prison for that charge alone.
A different man who was living in the area illegally is still wanted by Immigration and Customs Enforcement.
33 year-old Esteban Tomas is accused of causing a Mahomet woman's death on New Year's.'
State police say Tomas was driving the wrong way on I-74 when he hit Jeannie Brady's car head-on.
Anyone with information on his whereabouts is asked to call Homeland Security.