I never ever check luggage. I own a very nice large Tumi suitcase that I keep books in. I do not plan on using it, ever, unless I go somewhere for longer than six weeks, which is not likely to happen. So this is not my problem.
The problem is my father's. Last week, he flew IND-ATL-CDG-TXL, but because of various weather/ground/Hartsfield-related issues, he missed his ATL-CDG flight and was rebooked on a later ATL-AMS-TXL connection. No problem so far, stuff happens.
Because he was bringing some gifts for relatives back home, some of which were of the, say, liquid variety, he had to check a bag. (

) When the connection mishap happened, he went to a transfer agent at ATL and asked that they make sure that the luggage be taken care. The agent assured him it was in the system, and that there was no need to worry.
Well, of course, when he got to TXL, the bags were not there, nor was there anyone there at the KL luggage desk who was able to locate it anywhere in the massive DL/AF/KL system. He filled out all the forms, etc. etc. and went on his merry way.
The luggage was located after two days, sitting on its own somewhere in the bowels of Hartsfield, and eventually forwarded to my dad at his final destination. So far, no problem still, stuff happens, we're all seasoned flyers, we get it.
But this is what we don't get: when my father opened his suitcase, ALL the gifts were missing. Not his socks, not his undertrousers, not his favorite belt, just $300-$400 worth of gifts meant for relatives and kids of relatives. This may not seem like much, but it's sort of rude among our people to come home empty-handed.
Obviously thievery was involved, and I want to know how to resolve this issue. I am mostly done with DL, but he remains a loyal flyer, so I don't want his blood to boil over some knuckle-head in ATL who thought it'd be a good idea to go through someone's bags.
Who do I write to to seek regress? What do I say? I honestly want to throttle someone, but writing angry emails doesn't get one anywhere, so I would like some idea what to ask for, where to direct the complaint, etc. etc.
Many thanks, and sorry for the wordiness. I like to write.