Sussex Police have appealed for anyone who saw a fatal crash or who has footage of it to come forward.
The crash involved a green Ford camper van and a blue Honda motorbike and left the 31-year-old motorcyclist, from St Leonards, dead.
The crash happened close to the One Stop shop, in Blackman Avenue, St Leonards, and a police operation known as Op Glenside is under way.
The force said: “We are appealing for witnesses and information after a fatal collision in Blackman Avenue, St Leonards, on Monday 16 February at around 1.50pm.
“The collision involved a camper van and a motorbike.
“It was reported that the camper van collided with the motorcycle near the junction of Larkfield Close.
“One man was treated by paramedics. However, he was sadly declared deceased at the scene.
“His next of kin have been informed and our thoughts remain with them during this time.
“A 73-year-old man has been arrested on suspicion of causing death by dangerous driving.
“He has been bailed while inquiries are ongoing.
“Officers are investigating the collision and would particularly like to speak to anyone who saw this camper van in Blackman Avenue or the surrounding area prior to the collision.
“If you witnessed the incident or have relevant information such as CCTV, mobile or dashcam footage, we encourage you to report it to us online or by calling 101, quoting serial 727 of 16/02.”
