When it came to finding child care, Liza Rodman’s mother Betty wasn’t particular. As Rodman writes, “She’d stop people in the supermarket or at the post office or at the gas pump and ask, ‘Do you babysit?’” True to form, within five minutes of meeting Tony Costa, a newly hired handyman for the Provincetown, Cape Cod motel where she worked, Betty sent Liza and her little sister Louisa off with the stranger.

When it came to finding child care, Liza Rodman’s mother Betty wasn’t particular. As Rodman writes, "She’d stop people in the supermarket or at the post office or at the gas pump and ask, ‘Do you babysit?’" True to form, within five minutes of meeting Tony Costa, a newly hired handyman for the Provincetown, Cape Cod motel where she worked, Betty sent Liza and her little sister Louisa off with the stranger.

In her first book, co-authored with Jennifer Jordan, Rodman recounts her turbulent upbringing and her relationship with Costa, whom she knew as one of the few "kind and gentle adults" in her life.

Rodman was 10 years old when Costa disappeared in 1969. The author didn’t grasp why until decades later, when persistent nightmares prompted her to ask her mother what she remembered about Costa.

Betty’s blithe reply — "Well, I remember he turned out to be a serial killer" — sent Rodman reeling, prompting her to investigate Costa and, along the way, to revisit her girlhood.

Rodman and Jordan call The Babysitter "a hybrid work of memoir and narrative nonfiction," and the book’s structure reflects this, with chapters alternating between Rodman’s recollections and extensively researched accounts of Costa and his crimes. This technique creates a vibrant picture of the 1960s and the social changes that transformed the quiet fishing village of Provincetown into "P-town," a destination where "the weird and eccentric were celebrated, not persecuted."

Among these was Tony Costa, an intelligent and charismatic but dangerously troubled young man who grew to become a drug addict, dealer, petty criminal and deadbeat dad.

Nonetheless, he cultivated a "cool cat" persona and developed a Pied Piper-like following among P-town teens, calling them his "kid chicks."

No stranger to childhood loss and trauma, Costa’s hidden turmoil spilled out in ever-increasing violence until he murdered at least four young women — Sydney Monzon, Susan Perry, Pat Walsh and Mary Anne Wysocki — whose bodies he then raped, dismembered and buried in his "secret garden."

Perception is central to this story. Despite his considerable flaws, writes Rodman, "everybody thought Tony was great," to the extent that many supported him despite the overwhelming evidence of his crimes. Perhaps not surprisingly, Tony also considered himself "a victim."

As for Rodman, her mother hated and relentlessly abused her first-born both physically and emotionally. It is in the painful act of writing this book that Rodman’s self-perception shifts so that she no longer believes herself to be an "unlikable… unfixable… un-lovable" thing.

The Babysitter vividly describes how brokenness begets brokenness, how the lives of girls and women are inherently perilous, and how dangerous it can be to presume that children’s capacity for resilience is limitless.

Jess Woolford was born in Massachusetts and has walked Cape Cod’s beaches and woods.