There are really no similarities between Caleb and Elisa Lam, IMO other than both of them potentially crawling into an open water tank and not being able to get out again.
But there is a striking similarity between Caleb and Noah DeWitt, who's thread is now MIA here on WS for some reason. He went missing in 2015 in the middle of the night, reported by his roomates, not wearing shoes, found in a wet well of a sewage pump station, also in college, known to enjoy urban exploration.
'We're obviously devastated,' Noah DeWitt's mom says
While LE investigated it as a crime like they are doing here, it would seem the case was quietly closed and the assumption seemed to be that Noah put himself there to intentionally end his life. Someone kindly linked this towards the beginning of the thread but here it is again
How did a human body end up in the sewer?