A huge blaze which destroyed 550 bales of hay in Rotherham is being treated as arson.
The fire in a field off Field Lane, Whiston, was spotted at 7.40pm last Wednesday.
When crews arrived at the field, owned by Lawns Farm, they found hundreds of bales of hay engulfed in flames.
Police officers investigating the incident want to speak to a motorcyclist who alerted the farm owner to the blaze.
Two 19-year-old men arrested on suspicion of arson have been bailed pending further enquiries.
A South Yorkshire Police spokesman said: “Police in Rotherham need your help to trace a key witness following a reported arson at a farm in Whiston last week.
“At around 7.40pm on Wednesday 20 April, it is reported that around 550 bales of hay were set alight in a field off Field Lane, owned by Lawns Farm in Whiston.
“The fire caused significant damage.
“Officers believe a passing motorcyclist, who alerted the farm owner to the fire, may hold vital information about the incident.
“Are you the motorcyclist? Did you see the fire?”
Call South Yorkshire Police on 101.