Police said a black Ford Focus travelling on the A47 near Wisbech left the road and ended up on its side near a ditch.
The road was closed in both directions for several hours but has now re-opened.
More top news
The victim reported Samantha Watt to police in July after she discovered the photos had been put up on her Facebook page.
The roof and floors collapsed during the blaze at the property, one of Britain's finest Palladian mansions.
The BBC Three TV channel is to be made an online-only channel after the cost-cutting measure was approved by the BBC Trust.