Tripping by a kicker

[Ozofficial]

Can someone help me with an incident that occurred at a game last weekend?

Team A kicked off, and the kick returner for team B was tripped by team A's kicker.

Team A's kicker was flagged for a 15 yard penalty and ejected from the field.

It was definite trip, no more.

The matter is now going to a league tribunal and the kicker has been charged with assault that carries a minimum of a 6 game suspension.

I was under the impression that tripping the runner is legal under NCAA rules? Am I correct or were the officials correct to throw a flag, charge 15 yards and eject the player?

Your assistance is required ASAP!