Alright, so I know there are a few glitches with the forsworn conspiracy mission. the one i had was where after i completed the quest and escaped the mines/prison, all the guards still approached me, and brought up the dialogue 'I've been framed'. No matter what option you choose, it is an endless loop. This got very frustrating as I was unable to even go to the city without being approached/attacked.

the way to fix this involves following the stormcloaks story line. In that storyline you liberate the reach, which is the city of Markarth. for part of it you have to infiltrate the city and obtain proof that the steward still worships talos. What i had to do was basically fight my way up through the city killing every guard. enter the jarl's palace and kill everybody in there. Once you kill everybody you have to grab the talos amulet. However, the main people (the jarl, etc.) won't die, they just drop to one knee. So after you have the amulet you have to drop the steward to one knee, and then you can talk to him. This brings up the dialogue about him worshipping talos, and he tells you what you need to know. After this you can continue on with the quest line, and after another quest in the questline you liberate the city, replacing the imperial guards with stormcloaks! And there you have it, since the guards are now on your side, you are free to enter the city again safely.