John Cagle said he wakes up at night thinking about how close investigators came to finding Meredith Emerson.

A turn down a different trail might have led searchers to the 24-year-old hiker before it was too late.

Still fresh in Cagle's mind are the hours spent with her parents and his interview with Gary Michael Hilton, the scrawny vagabond who admitted he kidnapped Emerson from a North Georgia hiking trail just for money he expected she would —- but never did —- give him.

"The thing that bothers us, or me, is what was going through her mind —- what she was going through. That's troubling," said Cagle, a Georgia Bureau of Investigation agent who was lead investigator on the Emerson case. "I think about how close we came."

After 30 years with the GBI, Cagle, 53, is retiring from the bureau at the end of this month but will continue in law enforcement as head of the Dawson County Sheriff's Office criminal investigation division.

Cagle's experience is extensive, but geography put him in charge of the Emerson disappearance and murder case. Born, reared and still solidly anchored in the mountains, he leads the GBI's Cleveland office, which covers the three counties involved in the Hilton search —- Dawson, Towns and Union.

Emotionally, the Emerson case hit Cagle like no other.

"I've never had a case like this where I've got so close to the victim and her family," the investigator said.

He spent many hours talking with the dead woman's family —- reassuring, consoling and updating them on the very public case. Also, Meredith Emerson is the same age and bears a slight resemblance to Cagle's stepdaughter.

Unlike other cases he has worked, the investigator can't stop second-guessing himself in this one. He punishes himself for not thinking of everything even though numerous law enforcement agencies were involved and assigning their own agents tasks.

"Why didn't I think to check Dawson Forest?" he asked. Dawson Forest Wildlife Management Area is where Emerson's body was found Jan. 7.

'Absolutely evil' man

Searchers were dispatched to campgrounds in the nearby Amicalola Falls State Park, but they didn't go into wilderness areas where they might have found the campsite where Hilton held Emerson. Cagle wonders why they weren't sent deeper into the woods.

When police finally caught up with Hilton as he was cleaning out his van in DeKalb County, they found Emerson's clothing in a Dumpster. "The blood was still wet," Cagle said.

Investigators used the media to involve the public in the search for Hilton, putting out a description of the van and then a sketch and then his name. In the end, the tactic helped investigators find Hilton. But that same publicity also may have pushed him to kill Emerson when he did. When police captured Hilton, they found two days of The Atlanta Journal-Constitution —- with front-page stories about the search —- in Hilton's van, Cagle said.

Cagle spent time with the murderer in the Union County sheriff's private office, listening to graphic details of the three days Hilton had Emerson. He came away with the belief Hilton is "absolutely evil."

The investigator says now, "In my opinion, he would not have stopped killing."

On Thursday, a Leon County, Fla., grand jury indicted the 61-year-old Hilton on charges he killed Cheryl Dunlap, a 46-year-old nurse and Sunday school teacher who, like Emerson, went hiking and was found decapitated.

Law enforcement officers in North Carolina suspect Hilton —- though they have not charged him —- in the deaths of two elderly hikers, Irene and John Bryant.

In the Emerson case, as in others, Cagle employed a no-nonsense approach —- a quality some appreciated but others see as unnecessarily blunt.

For example, an e-mail was sent to the GBI complaining about Cagle's brusque responses to reporters when Emerson's body was discovered. He repeatedly refused to discuss specifics.

"He's very firm. Very direct," GBI Director Vernon Keenan said. "Sometimes law enforcement agency heads will get a little ruffled."

But Susan and David Emerson, Meredith's parents, were not offended.

They met the 6-foot-4 investigator in a cabin at Vogel State Park.

"He looked us in the eye and told us he would always be up front and honest with us," the Emersons wrote in an e-mail. "We knew by the way he looked at us that we could trust him. ... He stayed true to his word, was always compassionate, and always treated us with the utmost dignity and respect. We knew he saw Meredith as a person ... and not as a case number."

Tactics for drug cases

Before Meredith Emerson, Cagle's biggest homicide investigation was the 2006 killing of Sueann Ray. In that case, Cagle used the same investigative tactics employed in drug cases, according to the Pickens County prosecutor and an agent who worked with Cagle. Wiretaps, surveillance and informants were used to pressure Ray's husband, Quinton, who finally admitted he killed her and drew a map to where he had buried her body.

In contrast, the Emerson investigation was a basic manhunt. Witnesses who had seen Hilton or Emerson provided the details for a timeline of his movements.

Peggy Bailey, the Athens teacher who sat with the Emersons when they talked with investigators and who relayed the family's comments to reporters, said Cagle was "tactful" but told them everything.

"He didn't hedge," she said. "He didn't talk to us as if he couldn't tell us some things. He didn't pull punches."

He let himself get close, Bailey said. And he has stayed in touch with her and the Emersons since they returned home to Colorado.

Even if something happens with investigations of Hilton in the other states, Cagle warns them of possible media coverage.

"He's protecting us," Bailey said. "He's protecting a lot of people."