A burglar smashed a pane of glass to get into a house in Worthing.
The back door of the home was breached while the owners were out.
An intruder forced their way into a property on the north side of Pavilion Road between 6.30am and 9.45am today.
The victims returned to find their home had been searched.
It is not yet known what was taken.
Sussex Police launched Operation Magpie to tackle burglary across Sussex.
Detective Constable Mandy Taylor said the smashing glass would have made a loud noise so it is likely someone could have heard something.
She said: “If you were in the area and saw or heard anything suspicious we would like to speak to you.”
Anyone with information should call 101 quoting serial 414 of 31/07, email firstname.lastname@example.org or call the independent charity Crimestoppers anonymously on 0800 555111.