Assassin's Creed IV: Freedom Cry Walkthrough Part 6 – “A Scientific Inquiry”

Optional Objectives
Complete all 5 Investigations
Do not kill anyone while investigating

Bastienne will meet Adewale in the brothel and send him to investigate matters with the harbormaster and learn what is going on behind her back. Head over to the marker that sits down by the harbor. You will find it in a warehouse. Approach it from the South and slip inside. Be sure to slip in unnoticed and take out the guard inside. From there just go over to the eavesdrop and listen in from the balcony above. Once the eavesdrop is over then the optional objectives become active.

The first investigation is a courier to the Southwest of the warehouse you are in. Leave the warehouse and go over to the nearest ship to the West of you. Keep on the outside of the pier. When you are close to the ship, take up a corner position and lure in the Jailer who is nearby with a Whistle. Knock him out then use Eagle Vision to find your target. You will see a thief grab the package and swim for shore. Run along the pier to the beach that he is swimming toward. Tackle him then steal the package off him with a pickpocket. That will finish the first investigation.

The second investigation is to the South. You will find a Fisherman who has information. He wants you to free the slaves that his rival uses to fish up more than he does. The location is marked on your map. Head over there and quickly blend and pickpocket the fishmonger. Rush over to the cage and free the slaves after that. If you encounter trouble while opening the cage, then use Smoke Bombs and unarmed fighting to take down your opponents. Remember to not kill anyone

The third investigation is found in an alleyway to the East of the beach  As you head East inland you will find the marker for a pair of Scientists. You just need to eavesdrop on them. Keep behind the fence and then climb up onto the rooftop when needed. They will go through the alleyway and then turn to the the West. Follow them as they walk the streets over to the shack nearby the warehouse you started the investigations from.

The Fourth investigation is far to the South in Port-au-Prince. You need to interrogate a messenger. Head over to the Northeastern portion of it. Look around the building there to find a pair of men leaning against the Southern edge of the building. Use Eagle vision to find your target and get him running. Immediately tackle him and be done with it. Otherwise there is a simple chase through the town.

The final investigation is in the Northeastern portion of Port-au-Prince. Head into the search area. You will see a pair of men arm wrestling. Your target is there but first you need to be sure to get away with it. Go behind the guards to the Southeast and lob some firecrackers a short distance behind them. Move over to the pair of men as the fuse burns and the firecrackers begin to blow. When the guards have moved, use Eagle Vision to find your target and pickpocket him.

To move forward in the missions, you need to liberate the Wellington Plantation in the Caribbean Sea.