This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / Ben Jordan: Paranormal Investigator
In Case 3, Ben is actually nice to the person used as the sacrifice dummy which causes her to Become the Mask. Zortherus then kills her because she doesn't want to hurt him anymore.
Case 5 when Alice is almost killed by Yamamoto.
Case 6 when Ben is exploring the Sea People's lair. Sad music also plays when it's revealed they were Mis-blamed for the monster and that they died out long ago.
The end of Case 7.
Ben meeting Simon as a ghost in Case 8. Simon is understandably bitter at first but, when it's the moment to part ways, he tells Ben he wouldn't trade the adventures they had together with nothing else.