The Marowski Heist

The Marowski Heist is a quest in Fallout 4.

Detailed walkthrough
While in Diamond City after completing Diamond City Blues, Darcy Pembroke gives the Sole Survivor the Marowski heist photo. One can either show it to Marowski to tip him off that Malcom Latimer stole from him, or show it to Latimer to blackmail him.

Blackmailing Latimer

 * 1) Latimer will offer 400 caps for the photo, or 600 with a successful speech check. After handing over the photo, the quest ends.

Tipping off Marowski

 * 1) Go to Goodneighbor and show the photo to Marowski. He will give 500 caps.
 * With a successful speech check, he can be convinced to hand over the caps before seeing the photo. If the Sole Survivor then refuses to hand over the photo, Marowski becomes hostile.
 * 1) Marowski will ask the Sole Survivor to kill Malcom Latimer for another 300 caps (400 with a successful speech check)

Once the quest has been completed, you can return to Darcy Pembroke in Diamond City, and choose whether you want to split your caps earned from the quest with her.

Bugs

 * If you refuse to hand over the photo to Marowski after getting paid, the Marowski Heist quest is still active, but has no objectives.
 * If you bargained for 400 caps for killing Latimer, you still only get 300 after returning to Marowski.