Finding Brother Swarm

[Splendor]

So My PCs arrived in at Hergstag in the morning.
They found "evil" in a couple of the buildings with detect evil, but the houses were empty when they go in (being day time they wraith goes underground when the doors/windows are opened).
They figured whatever the "evil" is, was hiding from them. So they went inside closed the doors and the Paladin detected evil until something showed up. A small wraith, fight ensued.
So their current thinking is:
1) The small wraiths in the houses are the murdered children, who are hiding from the sunlight in their houses.
2) When the sun sets all the little wraiths will come out of their houses and kill them.
3) Something turned them into wraiths. They want to know what did it. 4) Maybe by killing that creature will make the small children wraiths die/rest.

So my question is, how in the world are they suppose to find where Brother Swarm's lair is? There seems to be no leads, nor even hints as to how the PCs are suppose to find it.

Note: The PCs have made it adamantly clear they plan to leave hergstag atleast 2 hours before sunset (so they don't have to deal with a wraith swarm).

[Griffyn Maddocks]

Spoiler:

They don't need to find Brother Swarm's lair or the bodies. That is just another clue. Check the Deductions section on page 16 for the clues that are helpful for the trial.

[Ben the Red]

Usually mentioning distictive things is enough to direct player attention. His lair is near the scarecrow on a hill, iirc, so mentioning something like, "As the sun sets, the scarecrow atop the hill casts a looming/ominous shadow." In my experience, simply mentioning something unique about an area can be enough to get players curious (good for red herrings too).

[Splendor]

Griffyn - The PCs want to find the creature that killed a town (they didn't do any real research before they came to hergstag) so it doesn't spread. They don't care about 'clues', they care about killing 'evil'.

Ben - I agree that simply mentioning anything will make PCs explore it. But they won't be in town at night nor at dusk. They don't want to be in a town where they think has 10+ wraiths in it.
---

They have noticed that there are no birds, nor animals in town. Maybe I can have the NPC suggest to scout around to see if any of the nearby area has a similar environmental factor.

[Ben the Red]

The idea is you want to put into their heads that they should go check out the scarecrow (which will lead them to the little cave with the skeleton).

Really it sounds like they put no effort into the investigation. If they did, they would know that 6 kids died. The first half of the adventure is all about searching for clues and using them to prove the Beast is innocent. If they don't, the Beast will be sentenced to death. You can remind them of their task to try and get them to search for clues (out of game) or have the lawyer/Daramid/another NPC ask them what they've found when they return (in game). When they come back empty, imply they are falling their task and hopefully they'll try to look for clues at the other two locations.

If the players don't like searching for clues/investigating, you may need to rework aspects of the campaign. There is a significant amount of detective work in the first 5 books.

[Rakshaka]

This thread is very the reason that I substituted the wraith-spawn children for Attic Whisperers and Brother Swarm as a Ghost variant; no group of PCs I know are going to stick around at a ghost town when the sun goes down (that all rhymed!), especially in a horror themed throw-down (and especially one with a strict timer). That said, Wraiths are highly intelligent, so I would use that aspect to motivate the players; maybe some of the children find the will to communicate their deathless suffering before they turn hungry and attack. These are tragic victims, not compulsive killers, so luring the PCs with sobbing, cries of help, or even blowing a spectral wind toward Brother Swarm's location could point them in the right direction.