Malcolm will eventually catch wind of the player killing his son during Diamond City Blues if the player doesn't keep Trish quiet and will confront them about it.
If the player convinces Malcolm (hard persuasion check) tat they weren't involved in Nelson's death, he'll offer them a contract to kill whomever the player implicates. The choices are Marowski and Paul Pembroke, with 400 caps to score (600 with a moderate persuasion check).
If rude in anyway, Malcolm will be convinced the player is responsible and will later attempt an assassination.
↑The Sole Survivor: "How did you get involved in something like the Marowski Heist?" Malcolm Latimer: "You wouldn't know it to look at me now, but I grew up a Lower. I ran with a rough crowd back then.But, unlike some, I made something of myself. I took my share of the Marowski Heist and now, I practically run Diamond City.Now about that photo. Do we have a deal?" (Malcolm Latimer's dialogue)