Video report by ITV News correspondent Paul Davies
The family of the soldier hacked to death in Woolwich paid tribute tonight to "a loving son, husband, father, brother and uncle", adding that he always wanted to be in the Army and "live life and enjoy himself".
Drummer Lee Rigby, 25, was killed by two assailants on the streets of south east London yesterday.
A total of four people including the two men shot by police have now been arrested in connection with the brutal attack.
Scotland Yard said a man and a woman, both 29, were held today on suspicion of conspiracy to murder and are being questioned at a police station in south London.
The two men who were shot, aged 22 and 28, have been arrested on suspicion of murder and remain in hospital in a stable condition with non life-threatening injuries.
Drummer Rigby's family issued the following tribute: "Lee was lovely. He would do anything for anybody, he always looked after his sisters and always protected them. He took a 'big brother' role with everyone.
"All he wanted to do from when he was a little boy, was be in the Army. He wanted to live life and enjoy himself. His family meant everything to him. He was a loving son, husband, father, brother, and uncle, and a friend to many.
"We ask that our privacy be respected at this difficult time."
Six residential addresses were being searched today as part of the investigation, three in south London, one in east London, one in north London and one in Lincolnshire.