I'll put this here, but I said much the same thing in another thread.
First, Deanna Holcomb is a former girlfriend of Damien's. She could be lying. And just because Damien liked to "hang out" in manholes (if this is true) doesn't prove that he committed the murders. As Cappuccino said, where is this tidbit of information in Jessie's stories?
It never ceases to amaze me that some people believe that some teens are telling the truth and others are lying. They accept as gospel truth the "stories" of a mentally challenged teen, a juvenile delinquent, a couple of tween girls who supposedly overheard a conversation and an estranged girlfriend with an obvious axe to grind, but discount as lies the testimony of those teens who actually interacted with one or more of the WMFree on May 5, 1993.
Second, the little boys were all "into" Teenaged Mutant Ninja Turtles at the time of the murders. All of the parents knew this, as most parents know of their child's likes and dislikes. TH almost let it slip at one point, starting to mention TMNT specifically but backtracking at the last minute. TH also mentioned the fact that Ryan, Chris' brother, suggested searching in "something that covers a whole or something," at the same time indicating with his hands the approximate size of the opening of a manhole. These statements are in his Pasdar depositions, IIRC.
IMO, the three little boys would not follow Damien and his friends down into a manhole as they didn't know them and, if they had seen them around town, they would probably have been afraid of Damien because he looked different. They are much more likely to respond to one of their fathers. They could have either allowed him into the manhole (which is not what I believe happened) or (IMO the more likely scenario) exited the manhole when he appeared at the opening and ordered them out.
So, again, IMO, TH went to the manhole (probably around 7 pm) and either went down into it or called them to come up. If he went down, he was attempting to discipline Stevie and it got out of hand. He had two witnesses who saw it happen and who were trapped with him at the time in the manhole. So, he silences them as well. If TH simply called down and ordered the boys up, then Stevie, the first to emerge, was probably backhanded and knocked unconscious, but TH may have believed that he killed Stevie at that time. The other boys, upon emerging, received similar blows to silence them. IMO, either way it happened, it began with Stevie being disciplined and the others being murdered to eliminate witnesses.