Have the clerics of Gruweas no means of scrying John or tracking him down? It seems odd that a religion so bent on following the law to the letter wouldn't have caught him by now.
He is not magically find able in any but the most powerful ways, which are not at the disposal of Grimhold. The mundane ways determined that after he was driven from the town, he fled pretty far away. Hundreds if not a thousand miles. There was also some thought that continuing to go after him might push some of the townsfolk that had abandoned Tommimao back into his camp. (Note this argument was made by the religion of Tfop which had gained the most from the Tommimao faithful). With bigger undead problems to manage, the powers that be in Grimhold let it be, although there is still and warrant and bounty out for him.
It is also a consideration that John is believed to have been one of the most powerful residents in Grimhold at the time of the civil strife, killing one of the other most powerful citizens. He was known to be a skilled horseman (his last name was taken from the breed of horse he rides), a noted spellcaster, and a user of firearms. It is assumed that in the decade since, he has only grown more skilled, although he is middle aged by now.
