A missing guinea pig, a red bike and helmet and a gold helmet.
It sounds like a riddle, but it's actually a case Brunswick police are taking on to help reunite a little girl with her beloved pet.
Investigators have been told Bobby and his owner Bianca had been playing in front of the Collier Crescent home at about 8am on Saturday.
When she checked back a short time later she found Bobby had been 'guinea-napped'.
Instead she found a red bike and gold helmet in the yard.
Senior Constable Ashleigh Thompson believes another child may have him and wants to speak with anyone who might know the bike's owner.
“Our priority in this case is getting Bobby home safe and well”, she said.