Who is Kilmar Abrego Garcia, the man the US must retrieve from an El Salvador prison?

Maryland Deportation Error - (ASSOCIATED PRESS)

Kilmar Abrego Garcia’s story appeared as if it would begin and end in his native El Salvador.

But the U.S. Supreme Court on Thursday ordered the Trump administration to facilitate his return to the U.S. from a notorious prison, rejecting the White House's claim that it couldn't retrieve the Salvadoran national after mistakenly deporting him.