The widow of a policemen who died in a triple stabbing has paid tribute to a "true friend and devoted father".
Pc Jon Henry was attacked after responding to reports of an assault on a window cleaner in Luton on Monday.
Mary Henry said her husband was the "light of my life" adding: "There are not enough words to describe him."
One of two other stabbed men is in a serious but stable condition. A man who was arrested after the stabbings had been granted leave to remain in the UK.
Detectives have also been granted more time to question him.
Speaking at a news conference on Tuesday, Mrs Henry said her husband was her "best friend" and a "family man".
She said he loved his daughter Maggie.
"People have asked me to say something about Jon, his life, his personality, his point of view but there are just not enough words to describe him," said Mrs Henry.
"Jon was my whole life until our daughter, Maggie, was born last year. Maggie made a huge difference to our lives but Jon took to fatherhood like a duck to water.
"He was good at his job and loved helping people and making a difference."
She said Jon was "fun-loving, a true friend, a loyal and devoted husband and father, a caring person who always had time for others, a man with a fantastic sense of humour".
Mrs Henry said she did not feel that the death would have been avoided if police were routinely armed.
"I don't think it would have made any difference," she said. "It was a tragic thing that happened and no one could have foreseen it."
Pc Henry's sister Georgina Brock visited the town's war memorial and had been touched by the floral tributes left by the people of Luton.
"Something like this make you realise that not everybody is a bad person," she said.
Chief Constable Gillian Parker said of 36-year-old Pc Henry: "His dedication to his duty cost him his life."
Pc Henry died at Luton and Dunstable Hospital where the two injured men are being treated.
One of them, a 55-year-old from Luton, was stabbed in the back. Police have not given details of the second man.
Pc Henry was attending 999 calls from two members of the public after a man, said by witnesses to be a window cleaner, was attacked with a knife in Luton town centre.
The constable attended in a marked police car and was with a number of other officers when he was wounded.
Police used a baton round and Taser stun gun to restrain the knifeman.
MAP OF THE STABBINGS
Pc Henry starts work at Buxton Road police station at 7am
Police receive 999 calls reporting an incident
Pc Henry and other officers are at the scene by about 7.18am
Pc Henry is fatally stabbed while attempting to deal with the incident
Two members of the public are also injured
Armed officers subdue a man with a Taser and a baton round