The Marina - GTA Online: The Contract

Exit the Agency to Investigate The Marina.

Fly to the location to find a green speed boat on a helicopter.

After killing some enemies, get on to the green boat.

Search the coardinates for the yacht on a green boat.

After finding the yacht, kill the guards using sniper rifle.

Board the yacht, after killing the guards.

Enter the main cabin, after boarding.

Go the the bridge after killing some more guards.

After getting inside, locate the door controls.

After unlocking them, Enter the main cabin.

Kill every guard inside and find the evidence.

After finding the evidence, take a photo of the evidence.

Send the picture to imani and wait for him to contact you.

Leave the area using a helicopter.

After that mission is going to be passed.