Charity Anne Johnson

However, Johnson's story unraveled when a friend she was staying with (who also believed Johnson's story) wanted her to leave her home.

Tamica Lincoln called police and told them she no longer wanted Johnson in her home. Johnson was then arrested after she gave them a false name and birth date.

According to jail records, Johnson is 31, although police later told US media the woman is instead 34.

The principal of the school where Johnson was studying, Stuart Newlin, said no one ever questioned her story and that she'd originally filled out her enrolment paperwork with a guardian in October.

In a statement he said: "She acted like a 15, 16-year-old. She was an attentive student, respectful, did her homework."

"The why? Nobody seems to know why."

34-year-old woman arrested for posing as a teenager