There are half a dozen Missing Persons Investigations in Watch Dogs, and each one of them will send you on the hunt for a corpse. You'll trigger the first of these investigations by completing the Backstage Pass mission in Act 1, or if you just happen to stumble across one of these bodies. If you've unlocked the nearby ctOS Tower, you'll be able to see each corpse marked on your map with a magnifying glass - that should make tracking them down much easier.
If you choose to start working on these investigations before completing the main storyline, just be aware that you won't be able to complete the bonus mission associated with this side-quest until you've completed Hope is a Sad Thing.
Missing Person - Chelsea Armstrong - Brandon Docks
Make your way to the south side of the bridge in this area. Now walk towards the water and look for a little nook that's tucked away beneath the bridge. When you climb up to it, you'll discover the corpse and the first audio log.
Missing Person - Debora Ingram - The Loop
Now take any boat that's nearby and make your way over to the island that's just on the eastern side of the map. As soon as you arrive, you'll be able to find the body in a rusty old shed that's on the north-eastern part of the area. Grab the audio log while you're here too.
Missing Person - Claudette Rousseau - Brandon Docks
Get back in your boat and then make your way to the southern part of Brandon Docks. To access the body marked by a magnifying glass on your mini-map, simply use one of the canals to the north and south of the body. When you arrive, get onto the second floor of the gutted factory to find both the corpse and the audio log.
Missing Person - Kate Quigley - Parker Square
Assuming you've unlocked the north Parker Square ctOS tower, use your fast-travel option to whizz over there. Get into a nearby car, then keep following the tracks until you come to a tunnel. Get inside to discover Kate's corpse and another audio log.
Missing Person - Alicia Freidkin - Pawnee
First, make your way into the north-western part of Pawnee. The body and the audio log can be found in one of the train cars along here. Investigate both, then get ready to track down the last of the killer's victims.
Missing Person - Annie Nelson - Pawnee
You'll find Annie to the east of the trailer park in the Pawnee district. Grab a dirt bike to make getting along the trail just a little easier. Annie herself is locked up in a cage inside a ramshackle building just off the road.
Crie for your daughter
Once you've grabbed your sixth and final audio log, it's time to take out the Finger Pain Killer and put an end to his killing spree. First things first, make your way to the trailer park and trigger the mission. As soon as it starts, grab your mobile and head towards the drained pool.
From here, you should be able to see your target by the pool's eastern fence. Walk all the way around and approach the objective from an easterly direction, using the trailer to stay out of sight. Don't be too keen to take out the killer here either - you must wait until his profile turns red or you'll fail the mission.
From your position of safety, take out your mobile to profile the killer's name of Edgar Noone. As soon as Edgar's profile becomes red, leap out of position and kill him quickly. When he's dead, go to the corpse and hack into his phone. You'll now have access to a tasty Chrome pistol, and you'll also pick up the Darkness Looms achievement or trophy at the same time.
You can find the rest of our Watch Dogs mission guide from the first page of this article.