Chasing the Skinsaw

After defeating the Ghast formerly known as Aldern Foxglove, heir and grandchild to Vorel Foxglove, the four Heroes find several pieces of evidence that lead them to Magnimar.

Haldmeer Grobaras, lord-mayor of Magnimar, is a bombastic and self-serving nobleman who sees his stewardship over the city as a reward for his hard work as an aristocrat and not as a service to his people.
Normally, the plight of the poor isn't his concern, he has people who have people to take care of those problems.
Yet this new plague of slayings is something else.
Merchants, nobles, bankers, and recently the proprietor of one of Haldmeer's favorite gambling dens have been slain, and it's no longer possible to discount theories that an entire cult of madmen might be involved.
Angry demands to stop the slayings fill the streets and taverns by day, and Haldmeer isn't sure that the frightened silence of the nights is much better.

Unfortunately, his rule of Magnimar has left the bureaucratic machine in bad need of a tune-up.
Magnimar's guards aren't equipped to handle a group as craft and sneaky as the Skinsaw Cult, especially with one of the city's Justices being charmed into Xanesha's service.

As a logical first step, Sagerius, Finn, Fletcher and Barthel investigate Aldern Foxglove's townhouse.
Unpleasantly surprised they encounter not only Iesha, but Aldern himself as well. After some back and forth they are attacked, and the creatures expose themselves as Faceless Stalkers.

After a thorough search they find a ledger and some documents indicating that Vorel had ties with an organization called 'Brothers of the Seven'.
Some quick research reveals that they have a sawmill in Magnimar where the Foxglove's have been sending regular payments.

The Seven's Sawmill is one of several mills that operate along the shores of Kyver's Islet. The mill is intended to look from the outside like a standard lumber mill, but while it does indeed produce lumber. the structure's primary purpose is to give the Brothers of the Seven a cover and a safe place to meet.

Built over the mouth of the Yondabakari River, this wood building sits on massive wooden pilings driven into the riverbed below.
A wooden boardwalk wraps around the northern rim of the building, and a flight of stairs leads down to a door on the east side just above the water level.
The churning of four large waterwheels under the mill fills the air with sound and mist.
The entirety of the first floor consists of a loading area. An opening in the ceiling into the floor above is filled with a tangle of ropes and slings for lowering timber.
Nearby, stairs ascend to the next floor. Two sturdy wagons sit to the south, next to a bank of machinery accessed by four low doors; the grinding and creaking of the machinery fills the room.

The Heroes from Sandpoint infiltrate the mill and eliminate the Cultists one by one, until they arrive at the top floor and encounter Justice Ironbriar himself.
With combined effort they beat him unconscious and loot his office.
Most importantly they find a journal in which he has recorded everything in cypher, using Draconic, Elven, and Infernal characters.
Using his skill in Decipher Script, Barthel sets out to decypher it.