Two men and two women are being questioned over death threats against a journalist following a story that a suspected criminal was arrested while wearing women’s underwear.
The four were among six people arrested on Monday after the intimidation forced Sunday World crime reporter Mick McCaffrey to leave his home.
Two people were later released without charge. The four still in custody are being detained under anti-gang legislation at Kevin Street Garda station in Dublin city.
The suspects were also questioned over threats made to a Dublin-based garda.
The inquiry began in July after the Sunday World published a story that a suspected hitman who had been stopped by gardaí in the Phoenix Park was wearing women's underwear.