Police in Northern Ireland have launched an attempted murder investigation after the shooting of an off-duty police officer in Omagh on Wednesday evening (22 February).The senior officer - who remains in critical condition - has been named as Detective Chief Inspector John Caldwell, and police said the primary focus of their investigation is on dissident republican group the New IRA.Mr Caldwell was shot multiple times by masked men in front of young people he had been coaching at a youth centre.