Police memorials say "here fell...." but i assume very few memorial stones are at the exact place a police officer died - and are placed at the closest convenient location? I
The problem is that it's not only often inconvenient to create a memorial in exact locations, it can also be insensitive, i.e.
For those of you old enough to remember PC Keith Blakelock being hacked to death in 1985 on the Broadwater Farm estate riots in London, I don't think his family would want a memorial plaque on the stairwell in the block of flats where the foul deed happened.
In Scotland, a memorial to all Scottish Police Officers who have died on duty is located at the Scottish Police College at Tulliallan Castle in Fife. It was inaugurated by Princess Anne about 5 or 6 years ago.