LONDON (AP) — Counterterrorism police on Saturday questioned a friend of alleged Islamic extremist Michael Adebolajo, one of two suspects in a savage killing of a British soldier on a London street that has horrified the country. The friend, Abu Nusaybah, was arrested immediately after he gave a BBC Television interview Friday describing how Adebolajo may have become radicalized in Kenya and alleging that Britain's security services tried to recruit him six months ago. Police said Nusaybah was wanted on suspicion of involvement in unspecified acts of terrorism. Adebolajo, 28, and Michael Adebowale, 22, are suspected of killing soldier Lee Rigby by hacking his body with knives and a meat cleaver in front of dozens of passersby Wednesday in the southeast London district of Woolwich. The horrific scene was recorded on witnesses' cellphones, and a video has emerged showing one of the two suspects making political statements and warning of more violence as the soldier lay on the ground. Police shot both men as they arrived minutes after Rigby's slaying. Both suspects remain under armed guard at two London hospitals. The attack has sparked fears of anti-Muslim sentiments in Britain. Police on Saturday arrested three people on suspicion of posting racist comments on Twitter, while Faith Matters, a charity campaigning against extremism, said its helpline has received 162 calls since Rigby was killed from people reporting anti-Muslim incidents including attacks against mosques. About 1,500 people took part in a march Saturday organized by the far-right group English Defense League in the northern city of Newcastle. Police said the march was mostly peaceful. The group, which has clashed violently with police in the past, has used Rigby's murder to criticize the British government for not paying enough attention to radical Islam in the country. Questions abound over what could have led the two men to attack Rigby, a 25-year-old ceremonial military drummer and machine-gunner who had served in Afghanistan and was off duty when he was walking near his barracks. Nusaybah's interview offered one possible narrative. He said Adebolajo's behavior changed after he allegedly suffered abuse at the hands of Kenyan security forces. Nusaybah said Adebolajo became withdrawn after he was allegedly arrested and then abused both physically and sexually while in jail. "Although that change wasn't necessarily one that became overt, aggressive or anything like that, he became ... less talkative. He wasn't his bubbly self," Nusaybah told the BBC. He claimed that agents from Britain's domestic spy agency, MI5, approached Adebolajo after he returned to Britain and initially asked him if he had met specific Muslim militants, then asked Adebolajo if he was willing to act as an informer. "He was explicit in that he refused to work for them," Nusaybah said. The BBC said police arrested Nusaybah outside its studios Friday night immediately after recording the interview. "This interviewee had important background information that sheds light on this horrific event," the BBC said in a statement. "And when we asked him to appear and interviewed him, we were not aware he was wanted for questioning by the police." London police confirmed that a 31-year-old man was arrested Friday night on suspicion of "the commission, preparation or instigation of acts of terrorism." Police declined to identify Nusaybah by name or provide further detail. It was not immediately possible to verify the information provided by Nusaybah, who said he had known Adebolajo for about a decade. MI5 does not publicly discuss its efforts to recruit informers. It is not uncommon, however, for special services officers to occasionally visit communities to ask people if they know potential terror suspects or others under MI5 surveillance. Potential informants go through a screening process to determine if they should be trusted, what their motivation might be and whether their information would be likely to be accurate. Nusaybah said Adebolajo was converted to Islam around 2004. His account corroborates those provided by two Muslim hard-liners who said they also knew Adebolajo. Anjem Choudary, a former leader of a banned British radical group called al-Muhajiroun, said Adebolajo was a Christian who converted to Islam around 2003. Choudary told The Associated Press that Adebolajo participated in several of the group's London demonstrations before Britain outlawed the group in 2010. Omar Bakri Muhammad, another former al-Muhajiroun leader and radical Muslim preacher, said Adebolajo is a Nigerian who was born and raised in Britain. He said that Adebolajo attended his London lectures in the early 2000s, but added that he had not stayed in touch with the suspect since then. Muhammad fled London and resettled in Lebanon in 2005 after suicide attacks on London's public transit system killed 56 people, including four bombers. "I don't know what Michael did since 2004 or 2005," Bakri told the AP. "Two years ago he stopped attending our open lectures and lessons as well as our activities." The University of Greenwich confirmed Saturday that records show Adebolajo was registered as a student there between 2003 and 2005. His academic progress was unsatisfactory and he did not complete his studies there, vice chancellor David Maguire said. The university did not have records for the second suspect, Adebowale. University officials are investigating whether there was any evidence of extremism on its campus, Maguire added. Police have not officially named the two suspects — officials in Britain usually wait to name suspects until charges have been filed. The AP has received confirmation of the identity of Adebowale from a British official speaking on condition of anonymity because they are not authorized to disclose the information. Few details have emerged about Adebowale besides one reported brush with death as a teenager. The Guardian reported Saturday that Adebowale was stabbed in 2008, when a man attacked him and two friends in a London apartment. One 18-year-old friend died and the attacker received a life sentence for murder, the newspaper said. Both suspects had been known to Britain's security services as part of previous terrorism investigations. Authorities said they have arrested three others, a man and two women, on suspicion of conspiracy to murder, but it is not yet clear whether the killing was part of any larger plot. The man remains in custody and the two women have been released without charge. MI5 Director-General Andrew Parker is expected to deliver a preliminary report next week to Parliament's Intelligence and Security Committee detailing what the agency knew about both suspects and whether MI5 could have done anything to stop the attack. The directors of Britain's foreign spy agency, MI6, and Britain's eavesdropping agency, GCHQ, also are expected to give reports on what intelligence they had on the two men. ___ Associated Press writer Paisley Dodds in London and Bassem Mroue in Beirut contributed to this report.