British police investigating the murder of lawmaker Jo Cox said Friday they were focusing on alleged links to far-right groups and reports that her suspected attacker, who remains in custody, was mentally ill.

West Yorkshire Police Chief Constable Dee Collins said the 52-year-old's mental health was a "clear line of enquiry" and reports linking him to right-wing extremists were "again a priority line of enquiry which will help us establish the motive for the attack".