The year is 1978, and the syndicated show "The Dating Game" is a household hit from coast to coast. A bachelor on one episode stands out for his looks and charm as he answers questions posed by a bachelorette in search of a date.
"Bachelor No. 1, what's your best time?" she asks.
"The best time is at night, nighttime," says the bachelor, whose name is Rodney Alcala.
"Why do you say that?" she asks.
"Because that's the only time there is."
What's wrong with morning or afternoon?"
"Well, they're OK, but nighttime is when it really gets good. Then you're really ready."
The bachelorette seems intrigued by 35-year-old Alcala. The audience also seems to think he's handsome and charming. In the end, Alcala wins the date.
But what the bachelorette doesn't know is that the man she just picked may turn out to be one of the most brutal and terrifying serial killers in history.
Watch the full story Thursday on "Nightline" at 11:35 p.m. ET.
"This could easily be another Ted Bundy," said Steve Hodel, a retired detective with the Los Angeles Police Department. "It could be 20, 30 victims." Now, 66-year-old Rodney Alcala is charged with murdering four California women and one girl in the late 1970s. Arguments in his multiple murder trial, in which he is representing himself, closed today. The case, at Orange County Criminal Courthouse in Santa Ana, Calif., is now in the hands of the jury.
Some investigators believe the five killings are just the tip of the iceberg.
"He's right up somewhere just below Hitler and right around Ted Bundy," said Det. Cliff Shepard, an LAPD cold case investigator. "There is no rhyme or reason for what he is doing. I mean it is not humane, whatever he does to these victims. It is a torturous, terrible murder."
By many accounts, Alcala was a man with a bright future. He had a Fine Arts degree from the University of California-Los Angeles, studied film at New York University and had worked for director Roman Polanski.
"I talked to his professor at UCLA and his professor came out and said this guy is a top honor student," said Hodel. "He is really a nice guy. He wouldn't hurt a fly. You've got the wrong man. ... I got this very smart, very polished guy and ... the acts he committed, you've got this monster inside of him."
Investigators said the slayings happened between late 1977 and mid-1979.
One of the alleged victims, Jill Barcomb, was a free spirit. In 1977, when she was just 18, she traveled from her home in Oneida, N.Y., out to California with friends. She was in Hollywood for only a few weeks when she met Alcala.
'He Gets Off on the Infliction of Pain'
Shepard took ABC News to the site where Barcomb's body was found.
"Jill's found right here," said Shepard, "around Franklin Canyon Drive, Nov. 10, 1977."
It isn't clear how Alcala allegedly picked up Barcomb, but police say the ending is certain.
"What he was doing was choking her out unconscious, bare-handed, and allowing her to regain consciousness because he enjoys that," said prosecutor Matt Murphy at Alcala's trial. "He gets off on the infliction of pain on other people."
Only one month later, prosecutors said, Alcala spotted beautiful 27-year-old Georgia Wixted, who had just recently moved into her first apartment.
"He followed her home. He crawled in her window and he absolutely brutalized her," said Murphy.
Wixted was found dead Dec. 16, 1977.
"He committed unspeakable acts of horror upon that beautiful young woman," said Murphy.
Police say Alcala likely spotted beautiful Charlotte Lamb in a local bar and tried to approach her.
"Before Rodney Alcala, just like the others, a beautiful young woman," said Murphy. "After Rodney Alcala she's a brutalized, ripped-up corpse."
Lamb was discovered in the laundry room of her building.
"He posed her dead body," said Murphy. "He propped her arms up under her back, probably to arch her up so that her breasts would be better exposed."
One year later, Alcala was spotted dancing at a bar with an attractive 21-year-old named Jill Parenteau. Just a few days later, Parenteau was found dead, her tortured body posed in almost the exact same fashion as Wixted and Lamb.
"Living alone, another independent person," said Shepard. "That was just another brutal, brutal murder."
Just six days after Parenteau's body was found, Alcala met his youngest victim, 12-year-old Robin Samsoe. The girl was riding her bicycle to her very first ballet class when Alcala allegedly convinced her to get in his car. Her body was found 12 days later.
"Robin was in the innocent child stage of 12," said Murphy. "All she cared about was ballet. ... He turned this beautiful young girl into a rotting corpse, eaten by animals."
Alcala has been twice convicted for the murder of Robin Samsoe, but both times the verdicts were overturned.
"I wish I had a gun again today," the girl's mother, Marianne Connely, told ABC News.
Connely was in court, once again facing her daughter's accused killer. During the first trial, in the days before metal detectors, she says she carried a pistol in her pocketbook when she took the stand, with the intent of making her own justice.
"He was blowing kisses at me across the courtroom, and I thought I was going to lose my mind," Connely said. "And I thought I was going to go crazy, you know. And I reached into my purse and I was going to grab it, you know, and I thought, 'I can't do this.'"
Police say Alcala has spent more than 30 years obsessing about the murder of Robin. He has even written a book proclaiming his innocence.
Robin's brother Tim Samsoe, 44, said the worst thing is watching Alcala perk up in court every time he get the chance to see old photographs of his alleged victims.
"You see the gleam in his eye," said Samsoe. "He's enjoying this again."
'More Out There'
Alcala is accused of using his skills as a photographer to lure his victims. Four different women still recall Alcala trying to get them to pose for him in their bikinis on the beach for a "photo contest" on the day Robin disappeared.
More than 1,000 photos taken by Alcala were found in a storage locker in Seattle, including bikini photos shot the day Samsoe disappeared.
"You walk up, camera in hand, polished demeanor," said Hodel. "You say, 'You want to be in pictures?' Basically, he was a skilled photographer."
There may be clues to countless other victims among photographs obtained exclusively by "Nightline."
"We know he's been cross-country a couple of times," said Shepard. "We know we have victims on the East Coast and the West Coast. We believe there's more out there. ... It wouldn't surprise me if we ended up with 10 to 15 more."
In New York City, authorities say there is evidence of at least two other murders committed by Alcala. But he has never been charged in those killings.
In early 1977, before returning to California, Alcala was studying at NYU and using the alias "John Berger," spelled like the English novelist.
Vanity Fair writer Sheila Weller's cousin, Ellen Jayne Hover, met a man calling himself John Berger at the time.
"He was a photographer," Weller recalled. "She wrote the name 'John Berger' in her address book and she disappeared." Hover was just 23 years old. She was a New York socialite whose father owned the nightclub Ciros and she was friends with Sammy Davis Jr. and Dean Martin. Hover's disappearance and murder was front page news.
"It was heartbreaking to everybody in her family," said Weller. "People don't forget these things, even years later. They don't forget the loveliness of a young woman and the absolute awfulness of this kind of a murder."
What may be most shocking about Alcala is his apparent ability to manipulate the legal system and nearly every person he has ever contacted.
In 1968, Hodel brought Alcala, then 25, to justice for his first known crime: the vicious rape and attempted murder of an 8-year-old girl.
"It was horrific," said Hodel. "What had happened was that he'd picked her up off the street, taken her into his apartment, his residence in Hollywood, and basically raped her -- again she was 8 years old -- raped her and then hit her over the head with a steel bar, leaving her for dead."
Alcala was convicted of the crime, but released after only three years in prison.
'The One That Took Him Down'
Alcala now faces five murder charges, but spent his entire closing argument rambling on about only one case: Robin Samsoe.
"Magical thinking, magical thinking is an irrational belief one can bring about a circumstance by thinking about it or wishing for it," said Alcala.
The victim's brother was there.
"It's the one that took him down," said Tim Samsoe. "He doesn't want to admit the one that took him down. It's a fluke now ... to him that the other ones came up. He thought he had it all beat."
Alcala said he couldn't have killed Robin. His proof was his appearance on "The Dating Game."
Investigators found an earring belonging to Robin in Alcala's Seattle storage locker. They said it linked him to the crime.
Alcala claimed he wore the earring on the show a year before Robin was murdered -- but in the clip from the show, it's not at all clear that Alcala was wearing an earring.
"I'm having to go through burying Robin four times now," said Tim Samsoe. "Nobody should have to bury their sister four times."
Rodney Alcala may have many more days in court, despite the pain and suffering the victims' family members endure. The state of California now has spent more money prosecuting him than any inmate in history.
"There's never an end to it, you know," said Connely, Robin's mother. "One minute it's over with, the next minute we're back in court. ... I still look at little blond girls when they walk past me to see if they'll turn around. ... I forget a lot of things, except the most important thing I can't forget, and that's her and how she died."