Jupiter contains a number of small moons that are thought to be captured comets or material ejected by collisions with larger objects. what is the evidence for this theory?

I believe the evidence for this theory is that:

The orbits surrounding Jupiter are highly elliptical which are off the plane of the ecliptic, and many of these moons are retrograde. This is very unlikely for moons or satellites which are formed during the planetary accretion. Hence comes the theory.