Actually, she’s being too modest. As a narrator, she’s fantastic: compassionate, psychologically astute and candid about her own biases and blind spots. The novel works so effectively because Haigh has created a thoughtful woman poised between doubt and belief. Without the self-righteous bitterness of an apostate or the willful certainty of the devout, Shelia hovers precariously, not sure what to believe about her brother’s faith or his sins.

In a preface to the main story, Sheila lays out Art’s early life and adolescence in swift, dramatic strokes, searching for the foundations of her brother’s character: early abandonment by his father, then a distant stepfather and finally the welcoming arms of the church. Though she doesn’t feel it herself, Sheila intuits the comfort that orthodoxy can provide a frightened young man. The collar, the pulpit, the vow of chastity — she understands that these aren’t burdens for Art so much as shields against the complex demands of adulthood. But how effectively, she wonders, can such a cloistered person handle the passions and strivings of being human?

Haigh raises these psychological inquiries in a story that repeatedly knocks our sympathies off balance. The action begins when Father Art is in his early 50s and feeling as though he’s lost his way. On Good Friday, 2002, as he contemplates the promise of new life, he receives a call from a church administrator. “He told me later that he’d had no idea why he’d been summoned,” Sheila writes, but that “seems incredible.” TV news vans have been stationed outside the chancery for months, hoping to catch the cardinal’s reaction to each new accusation of abuse. As soon as Art arrives, he’s calmly informed that he’s being placed on administrative leave. In this Kafkaesque scene, he’s not told “the name of the accuser; not even what he was supposed to have done.” But he must speak to no one and move out of the rectory that has been his home for years.

Everything Sheila relates to us is cast in shadows of regret and sorrow, and “Faith” certainly isn’t a thriller in any conventional sense, but it’s an incredibly suspenseful novel. What’s at stake isn’t just a child’s innocence or a man’s reputation, but a whole family’s faith and all the secrets they’ve kept neatly packed away like old christening gowns in the attic. Her vacillating belief in her brother’s virtue keeps us wondering as Sheila fills in the details of the incriminating evidence against him. He had taken a close interest in his housekeeper’s 8-year-old boy, but as Sheila notes, “When it comes to a man like my brother, nothing — nothing — is clear.”