|The following is based on Creation Club content and has not been confirmed by canon sources.|
Enter the Boston Bugle building and head to the second floor, which is guarded by a protectron. Once it has been defeated check the journal entries found on the terminal, which will add the objective to investigate the bookstore located in Monsignor Plaza. The plaza is inhabited by numerous raiders, and a turret. Once these threats are dealt with, head to the bookstore located on the lower floor.
There are three clues to be found in the bookstore, the quest markers for which only appear at extremely close distance. The first is a scratched subway token which can be found on the floor near the hole in the wall leading to the clothing store. The second is only mine, a note on a bookshelf underneath an advertisement for Boston Bugle. The third is a broken display case, which can be interacted with from behind the counter.
Once these clues have been found, the quest will update, sending the player to confront the murderer at College Square Station. The station, and the immediate area is infested with feral ghouls. On the bottom level of the station at the end of a collapsed tunnel a red doghouse is found, containing cap stashes and other loot. Pinned to the doghouse is a note which reads "Behind you". Immediately after closing the note the player is attacked by the Pint-Sized Slasher. Upon his defeat, the slasher's costume, knife, and a note explaining his motives can be looted ending the quest.