Most criminals aren't too bright, it's been my observation that the majority of them are functionally illiterate, not all, but most.
There are some that are quite intelligent, they often have other people doing crimes for them, they act as the mastermind. In Pott County we had a "Fagan", Fagan was a character in Oliver Twist who had children committing crimes for him, we had a 40+ yr old man that had juveniles committing burglaries for him, they would bring him the goods and he would pay them with narcotics. We dealt with him several times but he was smart enough that he never got any significant time.
The last time we served a search warrant we had the back door covered, when the guys knocked on the front door he went out the back, but he made a big mistake, he took a pistol with him. He was found with a pistol in his possession and was a multi convicted felon, the DA did something intelligent (for once), he got Federal Charges as a felon in possession of a firearm, 8 years with no parole as I recall, we were very tickled to get him off the streets for quite a while!