One of South America's most notorious serial killers admitted to racking up an incredible body count of 300 people. But how did a young Colombian named Pedro Lopez evolve into a vicious murderer? We investigate the events that could've caused Lopez to become the Monster of the Andes…


Every corner of Columbia was ravaged by fighting, riots and violence. The civil war had started in 1948, and lasted 10 savage years. There were beheadings, and crucifixions. Over 200,000 people were killed. And into this hardship and tragedy came a little boy.

Born in 1949, in a part of the country where the fighting was cruellest, Pedro Lopez’s life would be marked by violence long after his country had returned to peace. For this little boy would go on to take the lives of more than 300 young girls across South America. This was the boy who became the Monster of the Andes.

Pedro Lopez was the seventh of 13 children. His childhood was tough, brought up as he was surrounded by the extreme brutality of Colombia’s civil war. But there was no sense of stability or safety for Pedro, even when the doors of his family home were closed to the hard world outside.

Pedro’s mother was a prostitute. As a child, Pedro witnessed the flow of men arriving at the family home to have sex with his mother.

Our psychologist Dr Nicola Davies believes this is the reason Pedro became sexually aware at a very young age.

When he was only 8, his mother caught him fondling his sister. According to Dr Davies, Pedro was likely to have had sexual contact with his sister more through opportunity than desire.

But it would have serious consequences for Pedro. His mother kicked him out. Suddenly, the little boy had to fend for himself on those tough, frightening streets.

It was then he was picked up by an older man. This man promised Pedro food and shelter.

All was not what it seemed, though. Promises turned into lies. The man raped Pedro, then turned him out onto the streets once more.

‘Pedro was abused at a time when he was at his most vulnerable,’ Dr Davies says. ‘At rock bottom, this event could have been a turning point for Pedro, influencing which direction his life was to go. Already lacking trust in adults, the kindness of a stranger could have turned Pedro’s struggle with the world into a realisation that life is not all bad and that there is hope. Instead, Pedro’s fears about the world being dangerous were supported further, as was his conviction that for his own safety he had to go it alone.’

Monster Of The Andes 1980

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Rock bottom was not over yet for the growing man. He slept in doorways, scavenged for food. A life of crime perhaps seemed his only way out.

First, it was petty theft. But by the time he was a teenager, Pedro Lopez was stealing cars.

In 1969, though, the law caught up with him. He was sentenced to seven years in prison for the theft of cars.

But, two days after his time behind bars began, Pedro claimed he was gang-raped. Angry, he promised revenge. And Pedro was true to his word. He killed three of his four attackers.

‘Pedro was fed up of being the victim and this incident in prison made something click in Pedro’s brain – he would no longer be the victim,’ Dr Davies explains. ‘Although he was able to release a huge amount of rage when murdering three of the prisoners who raped him, Pedro had been through a lot prior to this incident – his anger would likely need further quenching and he had learnt one way to do that – through violence and murder.’

The prison authorities viewed the murder of his attackers as self-defence, and only added another two years to his sentence. He was released in 1978.

But Pedro’s vow of revenge wasn’t limited to his attackers. He wanted revenge on the world at large.

And so, he began his killing spree…

His victims were all young girls. First, he’d select them from the busy streets and markets of Colombia and its neighbouring countries. Then, he’d kidnap and rape them. Lastly, he’d strangle them to death, as he stared into their eyes.

Soon, he was killing three a week.

At one point, he was caught by members of a native tribe as he tried to kidnap a 9-year-old girl. They stripped him naked and, had it not been for the intervention of a local missionary, they would have executed him.

Pedro was free to kill again.

In an interview with police after his arrest, Pedro claimed he’d lost his innocence at the age of 8, when his mother had thrown him out for molesting his sister. He said it had been his aim to rid as many girls as possible of their innocence.

‘Pedro was so obsessed with innocence because he had lost his so young,’ Dr Davies says. ‘It is likely that he longed for his own innocence back, whilst also envying the young girls who became his victims. While most people have empathy, which makes them not want others to feel the pain they have experienced, most serial killers tend to lack empathy – they cannot put themselves in another person’s shoes.

Therefore, it is likely Pedro didn’t think about the pain he’d be causing these girls; his focus was on destroying the innocence he couldn’t have – these girls were merely ‘symbols’ of that innocence.’

Even his insistence on looking into his victims’ eyes reveals his obsession with innocence.

Ecuador Pedro Alonso Lopez

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In one interview, from his prison cell, Pedro said: ‘There is a wonderful moment when I have my hands round a young girl’s throat. I look in her eyes and see a certain spark go out.’

Dr Davies explains this.

‘By watching their faces, he would be able to watch their innocence disappear as their faces filled with fear and pain.’

Soon his victims totalled 300. Maybe more.

After the police finally caught up with him, he was sentenced to life.

However, Lopez is believed to have been secretly released in 1998, and his whereabouts are currently unknown, though Interpol have issued an advisory for his rearrest in connection with a murder in 2002.

‘At 8-years old, young Pedro is likely to have linked his own rape with fondling his sister – drawing the conclusion that he was punished for what he had done to his sister,’ Dr Davies sums up.  ‘His choice of victim – young girls – could have been his expression of anger towards his sister, who the adult Pedro might blame for the events he had endured as a child.’

Pedro’s was a life of cruelty. He’d been the victim of cruelty, and dished it out himself.

That innocents had to suffer in Pedro’s quest for revenge is perhaps the greatest cruelty of all.