It is often hard to believe that people will admit to things they didn’t do, but it happens more often than people believe. A pretty good summation of the phenomenon is right here.
“Scientists who study this phenomenon group false confessions into three general categories: (1) voluntary; (2) coerced-compliant, and (3) coerced-internalized. Voluntary confessors know what they are stating is untrue; the classic example is when aviator Charles Lindbergh’s baby was kidnapped and hundreds of people claimed responsibility. These people are often driven by intense feelings of delusion, guilt, or even desire for notoriety.”