British police today dramatically widened their investigation of the hacking death of a British soldier, arresting two suspects and raiding six homes after the assault that raised fears that terrorism had returned to London.
"This is a large, complex and fast-moving investigation which continues to develop," police said in a statement released to reporters. "Officers have been gathering information from witnesses, social media and a painstaking trawl of CCTV footage in the area is taking place."
Intelligence services admitted at the same time that they knew of the two men who allegedly killed the soldier Wednesday, a British security official told ABC News today, but the two weren't deemed enough of a threat to arrest or monitor.
The two arrested today -- one in South London -- are a man and woman, both 29, and both held on suspicion of conspiracy to murder, police said. Any connection to the Wednesday slaying is unclear.
Despite any progress, British intelligence will likely face questions about whether it should have been able to stop the assault.
The soldier who died in southeast London has been identified as Drummer Lee Rigby of the Royal Regiment of Fusiliers. "Drummer" is the equivalent of "private" in the Fusiliers, an infantry regiment in the British Army.
He was a veteran of Afghanistan, deployed to Helmand in 2009. Before he traveled to Afghanistan, he'd served as part of the Queen's Guard, standing duty outside London's royal palaces.
Outside the scene of the attack, officers combed, inch-by-inch, a parking garage and a lawn, and said they had recovered a "number of items."
One of the alleged attackers was a British Christian who converted to Islam, according to Anjem Choudary, the former leader of the group Al Muhajiroun, a banned Islamist Organization.
He is Michael Adebolajo, who converted to Islam in 2003 and changed his name to Mujahid, meaning one who wages jihad, Choudary told ABC News.
Choudary said Adebolajo was never a member of Al Muhajiroun but he knew him because he attended the group's rallies from about 2005 to 2011.
After 2011, Choudary said, Adebolajo stopped attending rallies. Choudary said he has no idea what Adebolajo has been doing since, and he said that Adebolajo never suggested any antipathy to British soldiers or any willingness to commit violence.
"He was a very peaceful man," Choudary said. "Never saw any kind of violence streak in him. Very quiet, timid man, in fact."
Adebolajo is under arrest in the hospital, recovering from bullet wounds he suffered when police shot him after he allegedly killed the British soldier.
He apparently had no intention of getting away, asking passersby to call the police and invited them to interview him on their camera phones. He spoke holding two bloody knives and his hands stained deep red, using rhetoric similar to that expressed in martyrdom videos.
"We swear by almighty Allah, we will never stop fighting you until you leave us alone, your people will never be safe," Abedolajo said calmly, according to ITV News, which first obtained the video. "Tell them to bring our troops back so we -- so you -- can all live in peace."
British police and politicians are concerned about blowback attacks, especially in the London district of Woolwich, the scene of Wednesday's attack, which has had a past history of racial tensions. A few hundred members of the anti-immigrant and right-wing party, the English Defense League, poured into Woolwich Wednesday night, wearing masks and throwing rocks at police. And police reported two separate attacks on Muslim centers in southern and eastern England.
Police in Essex, east of London, arrested a 43-year-old who was holding a knife outside a Muslim prayer center Wednesday night. They charged him with attempted arson as well as suspicion of possession of an offensive weapon, Essex police told ABC News.
And in Gillingham, Kent, which is south of London, another man was arrested Wednesday night outside a mosque on suspicion of racially aggravated criminal damage, Kent police told ABC News.
In response, an additional 1,200 cops are patrolling London today, according to Scotland Yard, focusing on mosques and religious centers, as well as outside army barracks.
And British Prime Minister David Cameron took pains to appeal to all Britons, emphasizing that the attack wasn't only on a single soldier.
"This was not just an attack on Britain and the British way of life. It was also a betrayal of Islam and of the Muslim communities who give so much to our country," Cameron told reporters.