A van ploughed into a canal in Southwick at around 2.20 this morning (Saturday).
Police, fire and rescue and the coastguard were called to reports a vehicle was submerged in more than five feet of water off the Lady Bee industrial estate in Albion Street.
The driver of the van - a white Vauxhall Astra - was not found.
A coastguard crew member told The Argus he believed the van had earlier been stolen from Southwick railway station. He added it was later pushed into the canal and abandoned.
He said: "There was no sign of life. We double checked the area to make sure no one was in the water or in the van."
A spokesman from Sussex Police said: "A member of public called to say there was a van in the canal. When we turned up there was nobody in there."
A spokesman from West Sussex Fire and Rescue service said: "The doors and windows were shut and the coastguard was also called out. We took no action."
Shoreham Coastguard tweeted: "Water rescue swimmer deployed from team, luckily no persons inside. Area search completed, nothing found."
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