A "well-respected serving police officer" died when she was hit by a van while cycling on a dual carriageway in Carmarthenshire.
Sgt Lynwen Thomas was declared dead at the scene of the crash at about 18:45 GMT on Thursday, on the westbound A40 near Bancyfelin.
The driver of the van was later arrested on suspicion of dangerous driving and has been released on bail.
Dyfed-Powys Police has appealed for witnesses to contact them.
Chief Constable Mark Collins said it was a "terribly sad day" for the force.
"It is with great sadness that we confirm the tragic and sudden loss of a member of the Dyfed-Powys Police family," the force added in a statement.
"Sergeant Lynwen Thomas was a well-respected serving police officer, who passed away following a collision yesterday evening.
"Our thoughts are with her family, friends and colleagues, who have all been offered specialist support."