A bag-snatcher on a bicycle pinched a bag of poo from an elderly dog-walker in Worthing.
The thief rode past the pensioner near the Post Office in High Street, Tarring, and grabbed a bag she had been using to clean up after her dog.
A spokeswoman for Sussex Police said: "A male on his pushbike came past her and snatched the bag, perhaps thinking that there was something of value inside.
"The lady was not harmed and clearly the thief stole nothing of value."
The crime took place at 10.45am on Sunday.
The suspect was described as a black teenager.
Anyone with information is asked to call Sussex Police on 0845 6070999.