Like the five other women who in recent years went missing or were found dead in the Chillicothe area, Tiffany Sayre struggled. All had battled drug addiction, according to authorities, and all were known to have frequented the same spots where the drug and sex trades thrived. Her family hoped that the 26-year-old Sayre would tire of such a life and come to terms with her inner demons. She never got the chance.

Like the five other women who in recent years went missing or were found dead in the Chillicothe area, Tiffany Sayre struggled.

All had battled drug addiction, according to authorities, and all were known to have frequented the same spots where the drug and sex trades thrived.

Her family hoped that the 26-year-old Sayre would tire of such a life and come to terms with her inner demons.

She never got the chance.

She went missing in May 2015; the next month, her body was found. Her death, blamed on a drug overdose, was ruled a homicide.

"I need to know why," said her aunt, Shelly Hehr.

"Somebody knows something. Somebody knows what happened to her."

The quest for answers, for closure, inspired Hehr, along with relatives of the other victims, to take part in a documentary series whose premiere is set for tonight on the Investigation Discovery network.

"The Vanishing Women," with six weekly installments, explores the tragic lives of the women and documents the ongoing law-enforcement investigations of their disappearances and slayings - which have raised fears of a serial killer in the Ross County city, about an hour south of Columbus.

The women, investigators say, knew one another:

• Sayre, whose body was found June 20, 2015.

• Timberly D. Claytor, 38, found May 29, 2015, in an abandoned home near Massieville. She was shot three times in the head. A man accused of killing her - the only arrest in the cases - is scheduled to stand trial next month.

• Shasta Himelrick, 20, found in January 2015. A coroner deemed her death a suicide by drowning, although relatives think she was killed.

• Tameka Lynch, 30, found in May 2014. Her death was ruled a drug overdose.

• Wanda J. Lemons, 39, last seen in October 2014.

• Charlotte E. Trego, 29, missing since May 2014.

It was after the disappearance of Sayre, the sixth victim, that the Chillicothe Police Department and Ross County sheriff's office formed a task force and enlisted the help of state and federal agencies.

Alhough not every death was called a homicide, authorities think foul play was involved in each - as the bodies were dumped in or near creeks and rivers, where the remains were found.

"We continue to investigate each of these as a homicide, given the fact that criminal offenses occurred," police detective Bud Lytle said. "We're fully aware that the bodies were moved after they were deceased."

Investigation Discovery is owned by Discovery Communications, which also owns the sister networks Discovery Channel, Animal Planet and TLC. After seeing the story of the Chillicothe women in the national media, the outlet partnered with Sirens Media to document the mystery.

"We didn't want to swoop in with a giant crew," said Jeanie Vink, an executive producer.

"We wanted to be intimate and respectful for people who are still going through a grieving process."

The long-form, episodic format - similar to that of "Serial" on NPR or "Making a Murderer" on Netflix - represents a departure for the true-crime network, which traditionally produces one-time documentaries, with each case closed at the end.

"That is different for us in terms of hoping people come back week after week, but this story is so gripping," Vink said. "Maybe we'll shake loose some leaves or get them some help in solving the cases."

A network crew remains in Ross County to follow updates, and producers continue to evaluate how to cover the upcoming trial of Jason A. McCrary - who was charged in July after DNA evidence on his shoes linked him to the Claytor slaying, investigators say.

The trial is scheduled to begin July 11, according to Ross County court records.

Investigators don't suspect McCrary in the deaths or disappearances of the other victims.

"The Vanishing Women," Vink said, has a sense of immediacy.

"I think it's relatable," she said. "It sort of shows you that it can happen anywhere."

Hehr, who was interviewed for the series, plans to watch every episode, even though she described the prospect of reliving the experience as "rough."

She occasionally visits her niece's two young daughters, in the custody of their grandmother.

Every time she sees them, she said, she is reminded of Sayre - whom she remembers as unfailingly kind and smart despite her troubles.

Hehr struggles with the thought that the girls will grow up without knowing what happened to their mother; she hopes, for their sake, that someone is prompted by the documentary to come forward with information.

"I think about it every day," she said. "I keep trying to think and figure it out."

Her niece, she said, was a good, honest person.

"She was always happy. She was very loving."

elagatta@dispatch.com

@EricLagatta