Police in the US state of Kentucky say a member of staff at a plant shot four people dead before killing himself.
The shooting, in the city of Henderson, happened after the employee at Atlantis Plastics had an argument with a supervisor, authorities said.
Police Lieutenant David Piller told AP news agency that two other people were injured in the killing spree and flown to hospitals in Evansville, Indiana.
Lt Piller said the employee used a handgun he got from home on his break.
A police spokesman told the BBC News website the shooting happened at just after midnight on Wednesday at 1218 (0418GMT).
He said one of the survivors was in a critical condition.
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