The commander of a policewoman killed when her patrol car was struck by a stolen 4x4 said he and fellow officers were devastated at the loss of a colleague they all loved.
Pc Philippa Reynolds, 27, from the Greater Belfast area, died when the unmarked car she was travelling in turned into the path of the speeding 4x4, which had just run a red light, in Londonderry at around 3.40am on Saturday.
Two men have been arrested by officers investigating the fatal incident on the Limavady Road.
Ms Reynolds, a former teacher, had been in the Police Service of Northern Ireland (PSNI) for two years.
Her commander in Derry, Chief Superintendent Stephen Cargin, paid tribute to her. He said: "She was enthusiastic, bubbly and had a beautiful personality. She was just loved by her colleagues and she turned that love to the community she served."
The patrol car was turning a corner when the stolen silver Toyota Land Cruiser hit it side on. Mr Cargin said he believed the officer, who was sitting in the rear driver's side seat, would have died instantly due to the force of the impact. Two other officers in the car sustained non-serious injuries.
Police had been hunting for two males that had made off from the scene in the direction of the Ebrington area. The arrested men are aged 23 and 25. They are currently being questioned in police custody. The Toyota was stolen in the Gobnascale area of Derry at around 3am.
Northern Ireland's chief constable has vowed to bring to justice those responsible.
Matt Baggott said he was greatly saddened by the death of his colleague. He said: "This is a personal tragedy for her family and also for the whole Police Service. She was out on duty, working to keep people safe, when she died. My thoughts and prayers are with her family at this time."
Northern Ireland Secretary Theresa Villiers said: "This is a tragic waste of a young life in sad and reckless circumstances. Constable Reynolds died as she went about her job keeping people safe in the community she served. I send my sincerest condolences to her bereaved family and colleagues. And I wish the two injured officers a full and quick recovery."