Saw an accident this morning

If a car infront (the description in the first post differs from post #4) of you and slows if you proceed to over / undertake the car you need to make sure the car is not turning, especially if there appears to be nothing in front of it causing it to slow down, it's basic road sense.

Didn't see #4. Bit stupid of the rider then. Still have to question whether there was sufficient indicator use.