Blown Koni or broken eibach spring?

[ptgrad2012]

Lately this week, I have been hearing faint knocking sound from driver rear side on the road.
Today I got out and saw the wheel gap on driver rear is lower than the passenger side's by ~0.5cm

Total mileage of my car is around 59000km
eibach prokit was put in 15750km
koni yellow was put in 32470km

anyway that I can find out which part is broken?
Thanks in advance

[Hyperion]

1. Jack up car see if spring is broken
If yes, stop here, buy new spring.
If no, continue to step 2.
2. Take off wheel, remove 17mm lower shock bolt and 2 12mm top bolts.
Compress by hand, if it takes forever to bounce back, buy new shock.