Kenneth Dean Thomas sent his stepson a post card.

The problem is: He did do so while both he and his stepson were behind bars at the Land O’ Lakes jail.

He wrote a note to his 17-year-old stepson that read “keep (your) mouth shut and you know the drill," according to the Pasco County Sheriff's Office. The stepson was behind bars in a different housing unit of the jail on charges of running a chop shop and auto theft stemming from a Sept. 28 arrest.

The post card was intercepted this week by deputies, who found it in the stepson's cell.

Thomas has been in jail since June on a charge of assault and domestic battery, which involved his stepson. He is now also charged with violating a domestic no-contact order.