They can start by looking here.

Via Emirates 24/7:

Saudi Arabia’s feared religious police authority has decided to launch a war against what it described as vice and sorcery accounts on Twitter inside the conservative Gulf kingdom, saying it aims to destroy all those accounts.

The Commission for the Promotion of Virtue and Prevention of Vice said it had formed special teams to track those accounts and arrest those who are behind them.

Quoted by the Saudi news network Al Arabiya, the Commission’s spokesman Ahmed Al Jardan said its members are watching those accounts which “are spreading vice and witchcraft” through the country’s society.

“We will track down all those who are behind these accounts whether they are men or women…we are determined to eliminate these accounts before they become widespread and out of control,” he said.