Officers responded to a fatal collision involving a cyclist and a van on the A40 westbound dual carriageway near Bancyfelin at around 6:40pm on Thursday, (Feb 25).
Tragically the female cyclist died at the scene.
In a statement Dyfed-Powys Police said:
“It is with great sadness that we confirm the tragic and sudden loss of a member of the Dyfed-Powys Police family.
“Sergeant Lynwen Thomas was a well-respected serving police officer, who passed away following a collision.
“Our thoughts are with her family, friends and colleagues, who have all been offered specialist support.
“We ask that family members are given the privacy they need at this difficult time.
“The driver of the van was arrested on suspicion of causing death by dangerous driving, and is currently in police custody.
“Enquiries into the circumstances of the collision are ongoing, and any witnesses are asked to come forward.
“If you saw the incident and have not yet spoken with police, if you might have seen the cyclist or van involved prior to the collision, or have dash cam footage, please contact the Serious Collision Unit as soon as possible.”