Looking back, Johnny Norman remembers Robert Charles Browne as a tough kid from a hard-luck family who had a quick mind and a bad temper.
Now, the kid Norman once taught in gym class in Coushatta, La., could turn out to be one of the nation's most prolific killers.
Browne, who is already serving a life sentence for killing a teenager, entered a Colorado Springs courtroom Thursday and pleaded guilty to killing another teenager, one ofhe claims to have killed dating back to 1970.
"He was a loner, but not somebody you'd expect to do this," Norman, now sheriff in Red River Parish, La., said in a telephone interview. "He did have a hot temper. In a pickup basketball game, somebody fouled him or hit him, he'd fly off the handle."
Investigators so far have been able to corroborate Browne's detailed claims in six more slayings, three in Louisiana, two in Texas and one in Arkansas, El Paso County Sheriff Terry Maketa said.
"It's possible he's exaggerating, but I don't think you can conduct business assuming he's exaggerating," Maketa said.
CBS News correspondent Jennifer Miller reports that Browne had details of the crimes that no one else could have had.
If Browne's claims prove true, he would be one of the most prolific killers in U.S. history. Gary Ridgway, Seattle's Green River Killer who in 2003 became the nation's deadliest convicted serial killer, admitted to 48 murders but once said he killed as many as 71 women, according to interview transcripts.
Browne's public defender, Bill Schoewe, did not return a call.
A 44-page affidavit paints a picture of a killer who met his victims, sometimes men but mostly women, in everyday situations: a motel bar, an apartment complex, even a convenience store where he worked.
In one case, Browne allegedly used ether to knock out a drunken woman he was seducing and then "used an ice pick on her." In another, authorities said he used ant killer to subdue a woman he later stabbed repeatedly with a screwdriver.
Authorities said Browne grew up the youngest of nine children in the northern Louisiana town of Coushatta, about 40 miles southeast of Shreveport. Norman, the sheriff, said the Browne family ran a dairy in the 1960s and had hard times. "He came from a tough family," he said.
He was married six times, Miller reports, and authorities said all his ex-wives are still alive.
Browne's former high school teacher told CBS News that Browne was competitive and had a temper, but wasn't too different from most kids.
"I remember him being kind of a loner. He wasn't one that had a lot of friends, but he had friends," the teacher said.
Browne, a high school dropout who got kicked out of the Army for drug use, said his killing spree began during a bar fight with a soldier in South Korea in 1970. Maketa said that claim has not been verified.
The other claims include 17 murders in Louisiana, nine in Colorado, seven in Texas, five in Arkansas, three in Mississippi, two each in California, New Mexico and Oklahoma, and one in Washington state, Maketa said.
Browne pleaded guilty in 1995 to kidnapping and murder in the 1991 death of Heather Dawn Church, 13, of Black Forest, a town north of Colorado Springs. On Thursday, he pleaded guilty to first-degree murder in the death of Rocio Sperry, a girl who was about 15 at the time of her death 19 years ago.
Investigator Charlie Hess said he believes the killer himself doesn't even know why he is confessing.
"Does he have a conscience? Is that what motivated him? I really have no idea and I'm not sure he knows," Hess said.
It was Browne who spurred investigators to take another look at his past when he sent an unsolicited letter to prosecutors in 2000.
"Seven sacred virgins entombed side by side, those less worthy are scattered wide," the letter says. "The score is you 1, the other team 48."
The letter included a map traced from an atlas, and it showed outlines of Colorado, Washington, California, New Mexico, Texas, Oklahoma, Louisiana, Arkansas and Mississippi. Browne wrote a number inside each state and the total was 48.
Authorities responded, but Browne clammed up for a while, then agreed to more discussions. Eventually, he began providing details on other slayings.
Retired Colorado Springs police investigator Lou Smit, famous for suggesting that 6-year-old JonBenet Ramsey's killer was an intruder, had helped authorities build the Church case. He said he always had a feeling Browne was something even worse.
"'I know a guy who might be a serial killer,'" he recalled telling fellow cold-case volunteers in 2002. They contacted Browne and the off-again, on-again discussions began again.
Browne was asked whether any of his victims ever got away.
He told investigators: "None ever got away; never gave the opportunity. If you're going to do it, just do it."