Arrest and conviction records aren't transferred automatically from courthouses to computers on the internet.
Those companies that advertise their services on sites like this hire people to go to courthouses, get the information, and then enter it in their computers.
If you go down to your courthouse, you might see one of them, sitting at a public terminal, and typing into a laptop. He probably makes minimum wage.
If your relative died some time ago, his "record" may not be on any computer at all, but in a giant book, in the basement of a courthouse, gathering dust.