"We don't really know whats it in I can say that for thousands of years we drew sea monsters beliving they lived in it. Surprising alot of stuff we found in those pictures were in the ocean. (Giant Squid recently ). Just makes you think what else is actually down there that we don't know about."
Not a bad idea but you might want to avoid the word dumping.
Burial at sea is the more common term.
More likely than not the writer was referring to Hawley Harvey Crippen. Check out the article at www.thehistorypress.co.uk/articles/the-notorious-case-of-dr-crippen/