Since then, the British press has tied her to other events, including the case of an al-Shabab prisoner in Britain who in November escaped by donning a woman's burqa.
Headlines in the Daily Mail and others proclaimed the cross-dressing fugitive to be a disciple linked to "the white widow" and the Kenya mall attackers — again, with no evidence.
Still other papers said "the white widow" had been spotted in Somalia and was thought to be plotting fresh atrocities.
They quoted "intelligence experts" saying she might have been headed to Yemen, another spot with a weak central government where terrorist groups have flourished.
The constant reports of Lewthwaite at the fore of the al-Shabab movement — even though the group has denied on its Twitter account that it uses women recruits — has sparked some skepticism about her possible role.
In Mombasa, Kenya, where the trial of her alleged accomplice in one of the plots is ongoing, Islamic community leader Abubakar Shariff Ahmed said he thinks Lewthwaite's story has taken on a mythology all its own.
"An English lady, with four kids, not by herself, and she can disappear?" he asked. "Scotland Yard is looking for her, the FBI, the ATPU (Kenya's counter-terror police) and she's still in Kenya? Come on."
Associated Press writers Paisley Dodds and Cassandra Vinograd in London; Tom Odula in Nairobi, Kenya and Jason Straziuso in Mombasa, Kenya and Gillian Gotora in Johannesburg contributed to this report.