Specialist searches are ongoing to locate missing 53-year-old Imrich.
On 28 November, a report was made concerning the safety of a possible diver off Porth Ysgaden on the Llyn Peninsula.
Imrich’s silver Ford Mondeo Titanium was located in a car park close to Porth Ysgaden, along with personal belongings.
Chief Inspector Stephen Pawson said: “We are keeping all lines of enquiry open and are appealing to anyone who might have seen Imrich to get in touch with us.
“Anyone in the area of Porth Ysgaden on 27 November or 28 November and hasn’t already been in touch is asked to make contact with us.
“You can contact us by calling 101, or via our website using the link below, quoting reference number Q179229.”