The officer was collecting money from a Scotmid shop in Old Edinburgh Road, Uddingston, South Lanarkshire, last Friday morning when a masked man approached him and stole a case of money. The security officer was uninjured but left badly shaken, police said.
The suspect made off in a black Vauxhall Astra, which headed towards Laburnum Road.
Ten minutes later, police were called to a report of a black Astra on fire in a nearby street.
A 26-year-old man has been arrested in connection with the incident.
Detective Inspector Kevin Jamieson said: "I would like to take this opportunity to thank local people for their help and assistance during this investigation. We welcome their co-operation and with their constant support we will continue to keep people safe."