When someone is caught committing a crime (mainly
one sexual in nature, but can refer to all crimes), with overwhelming evidence to prove they did it; in their defense, the culprit denies that they were the
one caught doing the crime.
Derived from the Shaggy song "It Wasn'
t Me", which describes a man being caught having sex with another woman by his
wife, and subsequently denying that it was him she actually saw.
When caught on video having sex with a 14 year old girl,
R.
Kelly employed the Shaggy Defense; he just denied that he was the
one in the video.