The front and rear number plates were stolen from a car in Thorplands on Monday, police have revealed.
The theft happened in Sidebrook Court, between 12.30pm and 6.30pm.
Stolen number plates are later often found by police to have been used during other crimes.
A Wootton Hall spokesman said: “Police are appealing for information after number plates were stolen from a car sometime between 12.30pm and 6.30pm on Tuesday, May 14.
“The front and back number plates were removed from a grey Fiat Punto, which was parked in Sidebrook Court, Northampton.
“The registration number is KO06 NCF.”