Does it seem like, for an incredibly overbearing government agency, the Ministry of Magic shows remarkably little interest in investigating magical deaths? Dumbledore’s mother and sister both died of, at best, involuntary manslaughter but it doesn’t seem the Ministry ever came after anyone.
kinda like the Vince Fosters of the wizarding world...
When Dumbledore was young the Ministry was no more intrusive than our government was when your grandpa was a kid.
There's a message in there somewhere...
It was in the early 1900s wasn’t it? A totally different time.
Well, it just may be a case of them happening so often, that the Ministry simply doesn't bother to investigate too deeply. Harry or any of the other kids could have died dozens of times just doing the "normal" everyday stuff that went on at Hogwart's.
Plus, it's natural for a bureaucracy to follow the path of least resistance. If the nearest surviving relative says Cousin Theodosius died horribly while testing a new potion he'd just mixed up, the Ministry bureaucrat is likely to just accept it rather than start checking for foul play. To do so makes his job much easier!