A Swiss border guard made an easy arrest after he spotted his own stolen bicycle in the back of a car during a routine search.

The Swiss officer working at the Thayngen border patrol station between Germany and Switzerland was surprised when he looked into a Polish man's car and recognised the mountain bike sticking out of the boot.

"He was really happy to get his bike back," said a colleague from the station.

The 24-year-old Pole claimed he had bought the bike from a stranger.

Police are now investigating the theft.