The man, who claims to be Fenton Meeks, states that the killer was his brother, Adam, who recently killed himself. Figuring he has to investigate such a claim, Doyle cuffs the man and they go for a drive in the direction of the Rose Garden where the victims' bodies are supposedly buried.

Along the way, the man recounts the story of his childhood that led up to this point. It seems that 12-year-old Fenton Meiks (MATT O'LEARY) and his 9-year-old brother, Adam (JEREMY SUMPTER), lived a relatively happy life with their single dad (BILL PAXTON). That is, until the father had a vision one night of an angel who informed him that God had chosen him to kill "demons" walking among them posing as humans.

While Adam believes his father, even when he starts to kill people on a "list" supposedly given to him by the angel, Fenton can't believe what's occurring. Even so, with no other family members to tell and nowhere to go, the boy feels trapped by what he sees as rampant insanity that's infected his dad and brother. As the man continues with his story of what happened then during his father's murder spree, he and Agent Doyle get closer to their destination and some surprising revelations.

After all, one doesn't believe in Santa, the Easter Bunny or the Tooth Fairy forever, no matter one's earlier steadfast belief in what they were told about them. Like it or not, at some point in time, kids eventually begin to break loose, if not entirely free from their parents' statements, beliefs or ideology.

Imagine then, if two siblings - one 12-years-old and the other his 9-year-old brother -- were at different stages of such belief patterns when their single father suddenly announced that God had sent an angel to inform him that he must now kill various demons living among them in the guise of ordinary humans.

That's the premise of "Frailty," a fairly intriguing but not altogether successful suspense thriller that marks the directorial debut of actor Bill Paxton who appears in the film as that father. As concocted by screenwriter Brent Hanley (who's also making his feature film debut), the film is told in the often irritating "I've got a tale to tell" fashion where contemporary scenes are interrupted but ultimately explained by flashback ones that make up the bulk of the effort.

As it unfolds, the film seems to be something of an examination of insanity posing as a thriller. Or is it a look at divine intervention and the never ending battle of good versus evil, or a case study of one of the worst kinds of child abuse possible? It's actually a bit of all three, although the fact that Paxton and Hanley conclude and thus leave the film in a nebulous state regarding what it's ultimately supposed to really be about somewhat lessens its impact.

Theme and messages aside, the filmmakers are obviously aiming at creating a taut and old-fashioned thriller, and their film occasionally delivers the goods. Paxton should be lauded for implying and/or having much of the violence occurring off camera rather than in the usual, in-your-face, blood and guts glory common in most contemporary thrillers.

In addition, the notion of a father killing in the name of God both in front of his children and then trying to get them involved obviously has an inherently creepy aura to it. The plot also uses that oldest boy as the viewer's identifying character of reason in all of the sudden madness and we thus sympathize and worry about him.

That ploy obviously works, even if some of what occurs gets a bit far-fetched and some of the developments and performances don't always quite ring true. For instance, the entire element of the FBI agent - played with a quirky blandness (if that's possible) by Powers Boothe ("Men of Honor," "U Turn") -- investigating the case doesn't have much gravity as we never really see it occurring (most of the exposition regarding the "God's Hand" serial killer spree is visually delivered in the opening credits sequence).

Then there's the fact that no one comes looking for the various victims, including a sheriff, or one of the boys when he's locked away for quite a long while. Those points won't necessarily come up when one's watching the film, but they'll likely do so afterwards, particularly if someone happens to bring them up. For me, however, a somewhat constant nagging problem is that things never quite always feel right regarding how everything plays out, both from a plot and performance perspective. Part of that presumably stems from the fact that the narrator who's relating the story of the flashback is obviously a bit untrustworthy, but it's hard to say whether that's just my impression or the filmmakers' intent.

What's obviously intended, though, is to throw the viewer for a loop with the surprise twist at the end. Actually it's really several smaller twists all wrapped up in one sequence, but that doesn't negate the fact that viewers will probably see at least one of them coming, or that the whole thing feels a bit too contrived rather than just a natural progression of the story. It's almost as if the twist came first and the story was built backwards from it.

All of that aside, and beyond some occasional credibility problems, most of the performances are decent for a film like this. Matthew McConaughey ("The Wedding Planner," "U-571") makes the most of a southern drawl to make his character seem that much more mysterious, but the majority of the film focuses on Bill Paxton ("U-571," "A Simple Plan") as the father and Matt O'Leary ("Domestic Disturbance") and Jeremy Sumpter (making his debut) as the traumatized kids.

Paxton is effectively creepy at times - more so in the confused rather than homicidal mode - while the young performers hold their own, with O'Leary getting the meatier and more difficult role to pull off (which he does nicely).

In the end, the film will be most remembered for its ending and the putting of children (both fictional and the real thing) in emotional harm's way regarding the material, rather than its examination of the various themes running through it. Decent if disturbing, but not quite as effective as it could and should have been, "Frailty" brings up some interesting points, but doesn't go far enough with them to turn this into the thought-provoking thriller it wants to be. The film rates as a 6 out of 10.