Authorities say it happened Sunday night at the William Penn Inn in Lower Gwynedd Township. Police Chief Paul Kenny says the man had staked out the reception for hours and was watching people take gifts from to the unlocked car afterward.
Police say he watched the bride put a box with thousands of dollars in gifts into the car and then took off with it.
Glen Bowie, the father of the bride, says family members now recall seeing someone lingering around the reception that didn't belong there. Investigators say surveillance camera images also show the suspect in several cases.
Police say he fled in a car before the thefts were discovered.