Ring thief coughs up evidence ... literally

Police say a man accused of stealing a ring coughed up the evidence while officers were questioning him.

Pictures of the two-carat diamond ring worth about $US20,000 ($A22,158) were sent to jewellers in the Joplin area after it was reported stolen when someone took the owner's purse from her car on Thursday.

The Joplin Globe reports that the owner of Newton's Jewelry recognised the ring when a man and woman came to his store a few hours after the theft and said they wanted to sell it.

Lt Newton and his staff stalled them and called police.

Police say the man swallowed the ring when officers arrived. While being questioned, he began to cough uncontrollably and eventually coughed up the ring.

The man and woman are charged with receiving stolen property.