NAIROBI, Kenya - A suspect in last week's killing of a British soldier on a London street was arrested in Kenya in 2010 while apparently preparing to train and fight with al-Qaeda-linked Somalian militants, an antiterrorism police official said Sunday.

Michael Adebolajo, who was carrying a British passport, was then handed over to British authorities in the East African country, another Kenyan official said.

The information surfaced as London's Metropolitan Police said specialist firearms officers arrested a man Sunday suspected of conspiring to murder British soldier Lee Rigby, 25. Police gave few details about the suspect, saying only that he is 22.

The arrest brought to nine the number of people who have been taken into custody in Rigby's killing. Two have been released without charge, and one was released on bail pending further questioning. No one has been charged.

Rigby, who had served in Afghanistan, was run over, then stabbed with knives Wednesday afternoon as he was walking near his barracks.

Adebolajo, 28, and Michael Adebowale, 22, the main suspects in the killing, were shot at the scene by police and are under armed guard in separate hospitals.

In 2010, Adebolajo was arrested with five others near Kenya's border with Somalia, Kenya's antiterrorism police unit chief Boniface Mwaniki told the Associated Press. Police believed Adebolajo was going to work with the Somalian militant group al-Shabab.

Mwaniki said Adebolajo was deported from Kenya after his arrest in 2010. Kenya's government spokesman said he was arrested under a different name.

"Kenya's government arrested Michael Olemindis Ndemolajo. We handed him to British security agents in Kenya, and he seems to have found his way to London and mutated to Michael Adebolajo," spokesman Muthui Kariuki said.