Or better still…
You sell your chewing gum with your DNA on it, very publicly on E-bay and tell all your friends so they can laugh at your silliness.. or more importantly can swear in court later that you sold said chewing gum.
Then commit a crime, something serious, say Murder and leave a piece of your chewing gum at the scene…..
Police come knocking at your door … some time later, obviously, it just took me 9 days, YES, 9 days to “get an appointment” to report a theft……. and arrest you for Murder…
Fortunately you have many witnesses who can verify that you sold the chewing gum. Police start nation-wide manhunt for professional hit man who is so clever that he buys chewing gum from a stranger to plant as incriminating evidence..
Meanwhile you sell your story to the tabloids and get away with the perfect crime…