Before you do this mission I advise you pack the annihilator RPG and the AR-2 with grenade Launcher.
I came about this mission purely by accident. Not sure if anyone else knows of this mission, so I posted how to do it here.
(Please note that I did get the Unkut DLC for the game)
Step 1 – Police station.
Go to the police station and make your way to the 3rd floor (The one where Shaundi hacked the computers) across the way there should be a door leading to the detective’s office. Go inside and you’ll see saints logos.
(Don’t worry about the police trying to gun you down they won’t unless you fire on them)
Step 2 – Audio Logs
Step into each logo and press the corresponding button to hear the audio logs. Follow them around the room and you’ll end up in the office at the back, activating this final logo will give you the phone Number for Dex.
Step 3 – The Church
Once you have the phone number give Dex a call. He’ll tell you to meet him at the Chruch in saints row. Go there and start the mission as normal.
The mission its self is not too hard, but having the lock on RPG with you will be a great help. After you complete the mission you get the eiswolf added to your garage. The car is fairly decent and customisable.
After the mission there is no point in contacting Dex anymore. As he will repeat the same thing over and over again.
As for the mission its self. Pretty straight forward, I will not spoil it.
If there are any other secret missions people know off please let me know in the comments.