API function

Hi,

I am looking at the code for particle replacement and have difficulty with a function : 

void CRemoval::processParticleOfInterest(int threadID, int particleOfInterestId)

I would like to know when and how this function is executed? And since markParticleOfInterest(particle.ID) must be called before this function to mark specific particles. Does it mean I could mark particles in step 2,4,5 in the following picture  and the processParticleOfInterest function is called between step 5 and 6 for every particle marked in the current timestep, no matter particles are marked in Particle factory, Contact model or body force?