Continuity mistake: There's a clock on the first victim's night stand. When she goes to bed, it's Tuesday, 11:06. When the murder happens a couple of hours later, it's still Tuesday, 1:13.
Continuity mistake: When Reid is talking there's a big crack at the top of the window that might be a problem since they're supposed to be flying. Then a few seconds later they cut back to him and it's filled with putty. (00:05:00 - 00:06:00)
Continuity mistake: When Rossi is in Zoe's bedroom the camera pans the room and we see the laptop on the desk with nothing on its lid, but in the closeup suddenly there's a large embroidered flower sticker on the laptop's lid, which vanishes again when Rossi lifts the lid.
Chosen answer: Back in Target Rich, a hitman named Giuseppe Montolo dies whilst being interrogated by Derek. The men who abducted Derek were hired by his father, Chazz, who seems to blame Derek for his son's death. It's explained further in A Beautiful Disaster.
Annabel Keeley