Michael Adebolajo horrified millions of people by appearing on camera with bloodied hands clutching a knife and a meat cleaver moments after killing Lee Rigby.
The 29-year-old, who was raised as a Christian, became a committed Islamic extremist who tried to join jihadis in east Africa, and then brought terror to the streets of the UK.
In the shocking footage he was seen ranting about how Muslims in other countries had to witness similar horrors to that which he and Michael Adebowale had wreaked in south east London.
Another film clip captured him charging towards police clutching a knife and a meat cleaver, and flying through the air after he was shot by the embattled marksmen.
Giving evidence in court, he only showed emotion when talking about his religious beliefs, but remained calm when describing his chilling attempts to decapitate Fusilier Rigby.
He told jurors that he had converted to Islam in 2002 or 2003, when he was a student at the University of Greenwich, and chose to take the name Mujahid Abu Hamza.
Adebolajo said he wanted to be called Mujahid, meaning fighter, after he learned "how much Allah loves the mujahideen".
He was born to Nigerian parents at King's College Hospital in south east London on December 10 1984, and later went to Marshalls Park School in Romford, east London, where he made friends with Kirk Redpath, who went on to become a Lance Corporal in the British Army and was killed in an explosion in Iraq.
Adebolajo told jurors that most of his friends growing up were white British, and that he blamed Tony Blair for Mr Redpath's death.
His nurse father Anthony and social worker mother Tina had tried to dissuade him away from the clutches of Islamic extremism, but in 2010 he was arrested in Kenya, apparently trying to get to Somalia to join the terrorist group al-Shabaab.
Adebolajo said he wanted to get to the African country so that he could live under Sharia law.
His friend Abu Nusaybah claimed that Adebolajo was asked to work for the British security services after he was caught, and Adebolajo told police that MI5 had visited his home.
The Commons Intelligence and Security Committee is looking at what security services knew about the suspects before the murder, and is expected to make at least some parts of its findings public.
In police interview and throughout his court appearances he rambled on about his political and religious motivations.
Before his defence case began, a hearing took place to establish ground rules for what would happen in court, to try to stop him using the Old Bailey as his soap box.
Mr Justice Sweeney told his barrister David Gottlieb: "In the light of what we all saw in the (police) interviews what needs to be clearly understood is that in the court arena at least a question is not a cue for a speech, it's a cue for an answer."
Adebolajo was held at high security Belmarsh prison after he was charged with the murder of Fusilier Rigby, and there he claimed that he was attacked by a group of prison officers, and lost his front teeth when they put him under restraint.
Five members of prison staff were suspended after the incident, but the Prison Officers' Association insisted that only approved restraint techniques had been used.
Michael Adebowale attacked three police officers in his first 24 hours in custody, it can now be reported.
The 22-year-old, who was confronted by courageous "Woolwich Angel" Ingrid Loyau-Kennett in the aftermath of Fusilier Rigby's murder, was said to be "very unpredictable" when held by police.
As a teenager he was victim to a knife attack in which his best friend was killed, and he told psychiatrists that he was haunted by the voices of his would-be killers.
He was discharged from hospital six days after Fusilier Rigby's murder, and was formally charged on May 29, appearing in court for the first time the next day.
There the rare step was taken of allowing him to be handcuffed while in the dock because of the risk to police, prison and security officers.
It emerged that he had attacked three police officers in 24 hours. The first incident was when he was in his cell picking out his stitches, and when a police officer came in to stop him, he punched him in the face with his right hand.
Then when he was interviewed for the first time, he spat in an officer's face; and in a third incident he spat in a glass of water and threw it in a police officer's face.
While in prison he told psychiatrist Dr Neil Boast that he would hear voices in the morning for about 10 minutes.
The medic described: "People he doesn't know and people who took part in an assault on him when he was injured and a friend was killed. He hears people he doesn't know speaking in a Nigerian accent about him."
Experts said he had suffered post-traumatic stress disorder after being a victim of the knife attack at the age of 16. Police said he was "quite a troubled young man" who had gone missing from home more than once.
Former bare-knuckle fighter Lee James was found guilty of murdering 18-year-old Faridon Alizada in 2008 at a flat in Erith, south east London, and wounding Adebowale and another 16-year-old friend.
Adebowale, who was known as Tobi, was the son of Juliet Obasuyi, reportedly a probation officer, and his father Adeniyi, who works for the Nigerian High Commission.
He was raised as a Christian in south east London, and went to school in Kidbrooke. As he moved into his teens, he became involved in drugs and was linked to the Woolwich Boys gang - as was Adebolajo.
His concerned mother appealed for her friend Richard Taylor, the father of tragic Damilola who was killed at the age of 10 in a knife attack, to mentor her son, but he later fell into extremism.
Mr Taylor said that he was "terribly shocked" to see him involved in the brutality, having spoken to him only two months before the murder, but that he felt there was nothing that could have changed the 22-year-old.
In an interview with ITV News, he said: "Having seen how my own son was stabbed to death, it made me feel that...at the end of whatever happens, they will still be alive, they will still be on the street or maybe they will take them away from the public and go and change their faces. They don't deserve to live."
Adebowale, who asked to be called Ismail Ibn Abdullah in court, ultimately chose not to give evidence and refused to explain his horrific actions to the jury or Fusilier Rigby's family.