Karthik should prove his innocence to Raji's father in this matter. Raji doesn't need proofs but as a father he has every right to be angry on Karthik and suspect him when HR manager told him that karthik is culprit.
They should find real culprit soon. Karthik should start working on it. May be he is doing that already.
Once this is clear Raji's father when time comes will give his consent to K/R relation.
Am still curious to know their first gift.