A man has died after falling from a bridge on the A249 into the path of a lorry.
The road has now reopened more than 16 hours after the tragic incident, which happened at around midnight on the southbound carriageway at its junction with Key Street.
The man was pronounced dead at the scene. A report will be sent to the coroner.
Officers would like to hear from anybody who was travelling along the A249 near Sittingbourne or in the vicinity of the Key Street roundabout at the time of the incident.
They are also asking motorists with dashcams to check for footage that may assist their investigation.
A witness who was driving past at the time said: “I still see pictures of it in my head. I’m meant to be heading back that way tonight but I don’t know if I want to."
He called the emergency services.
The road reopened at 4.20pm after the incident caused massive delays with motorists stuck for more than two hours and the Isle of Sheppey essentially cut off during the morning.
Speaking to KentOnline earlier, Sheppey motorist David Nurden said: "All of Key Street roundabout is still closed off by the police.
"It's traffic chaos. I was going from Sheppey to Aylesford and joined the queue on the A249 at the Kemsley turn-off.
"Suddenly everything was at a standstill. It was solid traffic. It took me one-and-a-half hours to get from Kemsley to Bobbing and then another half-an-hour to get from Bobbing to Key Street."
Two fire engines from Kent Fire and Rescue Service were also at the scene. They received the call just before midnight and remained on site assisting other emergency services until 4am.
Anyone with information is urged to call Kent Police on 01795 419119, quoting reference 28-1562.