Throughout the 1970s, Rodney Alcala murdered at least seven women across California and New York, becoming one of the most notorious serial killers of the 20th Century.

But while most killers operate in the shadows, Alcala preferred the spotlight. He became an unlikely winner on ABC's long-running game show The Dating Game, where he successfully charmed a young lady on television, in front of millions of viewers, while in the middle of a prolific killing spree.

Alcala's youth was a troubled one.

He was born in Texas and moved to Mexico when he was eight. His father abandoned the family three years later, and Alcala wound up in L.A.

He dropped out of school at 17 and joined the army, but quickly suffered a nervous breakdown and was discharged; the military diagnosed him with anti-social personality disorder.

This would be the first in a laundry list of diagnoses levelled at Alcala over the years: borderline personality disorder; sexual sadism comorbidity; psychopathy; narcissistic personality disorder.

Unfortunately, many of these proposed disorders came after Alcala was arrested in 1979. A year earlier he was one of three 'bachelors' vying for the heart of contestant Cheryl Bradshaw. Alcala turned on the TV charm.

"Oh yeah, I remember it quite clearly," Jed Mills, the contestant who sat next to Alcala on the show, told CNN some 38 years after the appearance. "He was creepy. Definitely creepy."

Shockingly, at the time of the show's shoot, Alcala had already been charged with the 1968 assault of an eight-year-old girl, and had even briefly landed on the FBI's Ten Most Wanted Fugitives in 1971 after fleeing the state before arrest.

The Dating Game clearly didn't vet its contestants thoroughly — if at all.

"Something about him, I could not be near him," Mr Mills said of watching the tapes back. "I am kind of bending toward the other guy to get away from him, and I don't know if I did that consciously. But thinking back on that, I probably did."

In the green room before filming, he recalled Alcala as being "very obnoxious and creepy", and "very unlikable and rude and imposing as though he was trying to intimidate."

Mr Mills tried to keep his distance.

"He got creepier and more negative. He was a standout creepy guy in my life."

While Mr Mills' recollections may have been sharpened and coloured by the subsequent facts that came to light, there is no doubt that something was a little off with Alcala.

The psychology of someone who takes time during a prolific murder spree to appear on a frothy television dating show is too complex to enter into here, but the actual footage from the show is surreal, if only in hindsight.

Alcala was introduced by the host as a "successful photographer" who got his start in the trade when he was a mere teenager.

This otherwise chirpy description of Alcala takes on darker implications when considering that at the time of his murder arrest, just a year after his TV appearance, detectives uncovered just over a thousand photographs Alcala had taken of various men, women and children.

The subjects were always naked; the majority of the photos were sexually explicit.

In 2010, both the New York and Huntington Beach police departments released a cache of 120 of these photos to the public, in the hopes of identifying any of the people featured. Around 900 of the pictures were not made public as they were either too explicit or involved child pornography.

Within weeks, 21 women came forward as the subject of photographs; more tragically, six missing persons were also identified during this early stage.

Police were certain that many of these photos contained Alcala's victims.

Despite this, none of the photographs were definitively linked to any murders until 2013, when the family of Christine Thornton — whose body was found in 1982 — recognised her photo among the chilling collection.

"We fear he is one of the most prolific serial killers on the West Coast in the 1970s, up there with Ted Bundy," Orange County Deputy District lawyer Matt Murphy said at the time of releasing the cache of photos.

"He is a predatory monster, and when you see all these young women in positions of vulnerability with him, it makes you fear what happened to them."

One person who didn't suspect Alcala's predatory ways — at least not upon first impressions — was Ms Bradshaw, the women who weighed up the three potential partners on The Dating Game.

Watch the footage of Ms Bradshaw. It takes on a B grade movie quality when armed with the knowledge that Alcala was in the middle of a killing spree.

"What's your best time?" she asked him off the bat.

"The best time is at night," Alcala grinned. "Night-time."

She was sufficiently charmed to choose Alcala as her bachelor, but the date never happened; she backed out for undisclosed reasons.

Alcala was sentenced to death in 2010 for five murders.

Since then he has been charged with two further murders, and implicated in two others.

His actual victim count is presumed to be a lot higher.

"Bachelor No. 1 is a successful photographer who got his start when his father found him in the dark room at the age of 13, fully developed.

"Between takes you might find him skydiving or motor-cycling. Please welcome Rodney Alcala."