True Story by Michael Finkel
Michael Finkel was a top New York Times Magazine journalist publicly fired and disgraced for making up a composite character for a big investigative news piece about Africa. This book is about how this brilliant, high achieving journalist found himself at that point in his life. But in parallel it's also about Christian Longo, a man accused of the multiple murder of his own wife and three children.
After the deaths, Longo fled to Mexico, where he passed himself off as Michael Finkel, New York Times journalist. These two weird stories come together as Finkel in turn becomes fascinated (perhaps obsessed) with Longo the accused murderer, who while in prison and during his trial would talk only to Finkel. Who is using whom...?