Officers want to speak to anyone who was travelling on the A472 between 3pm and 4pm on Saturday 9 September.
We received a report of a road traffic collision on the A472 travelling from Nelson towards Tredomen at around 4pm on Saturday 9 September.
Officers attended, along with personnel from the Welsh Ambulance Service and Air Ambulance Service. The collision involved a motorbike.
The rider, a 50-year-old man, was sadly pronounced dead at the scene.
His next of kin have been informed and are being supported by specialist officers.
Officers investigating the collision want to speak to any motorists who were travelling on the A472 who witnessed the collision between 3pm and 4pm on Saturday 9 September or anyone with dashcam or CCTV footage to contact us.
Call 101, quoting log reference 2300305278, or send us a direct message on social media.