His first visit to Rwanda was in 1990, as a young student who had come to see the mountain gorillas, for the first time.
At the time, he sensed too much tension in the country, when his friend that he had come with, was prohibited from leaving the capital to see the gorillas because he had declared himself as a journalist on his entry visa.
"They thought he was investigating their dirty secrets, so he was put under house arrest and never got to see the gorillas. That alerted me to the fact that this is a country with some secrets," he says in an exclusive interview with The New Times.
A few years later, after the Genocide against the Tutsi, Andrew Wallis, a British freelance journalist and researcher, started researching about the Genocide which led to his first book Silent Accomplice: The Role of France in the Rwandan Genocide.
He has been researching on the history of Rwanda for many years.
Specifically, over the past seven years, he has dedicated all his time to his new book 'Stepp'd in Blood: Akazu and the Architects of the Rwandan Genocide against the Tutsi'.
"It took me seven years, spending most of the years in the ICTR in Arusha, archives in Berlin, Belgium, London and Rwanda. I've been very fortunate that I've had a lot of help from many people who've given their time and appreciated the importance of the subject," said Wallis, who was recently in the country for the International Conference on the Genocide against the Tutsi.
"I'm a historian and to me history shapes the future, if you don't understand your history it will repeat itself," he says.
The book gives a sneak peek into events that led to the 1994 Genocide and how politics played a major role, starting with the regime of Grégoire Kayibanda, the first President.
The book, he hopes, will shed light on the crimes of the perpetrators and show the world who they are, what they've done and what they were willing to do with their ambitions.
"I found it surprising that while everyone in the West knew about who committed the Holocaust (against Jews), this was a terrible crime that happened here but no one knows who the criminals are and, without the criminals, it's easy to say there's no crime and deny it.
"I thought it's important to spell out and shed a light to these people like Anatole Nsengiyumva, Augustin Ndindiliyimana, Felicien Kabuga... they all stayed in this sort of nice dark quiet place and all the spotlight is put on the current government here," he says.
Nsengiyumva and Ndindiliyimana were senior military officers during the Genocide against the Tutsi and testimonies abound on their role in the massacre of Tutsis, but were both acquitted by the ICTR.
On the other hand, Kabuga remains a fugitive, despite his overwhelming role as the financier of the Genocide, as he has come to be known.
Wallis adds that although many books have been written on the Genocide, most only focus on the events of 1994.
"Yet these criminals didn't just appear in April 1994. "You have to go back to the 80s and 70s and 60s to find out who they are, how they took power, how they grew their wealth, and what I'm exploring is how in the 70s and 80s, this mafia group really took power in Rwanda.
"That, to me, is a story that is perhaps not well known but is really important to discover what, in 1994, these people were really protecting because the Genocide presents itself as ethnic killings but actually it's political.
He adds; "Some politicians who designed it, organised to protect their power and wealth and, if it meant sacrificing a million people, that was a price they were happy to pay, to keep in power.
"What happened in 1994 was a repeat of 30 years earlier, and how the West reacted was always the same. History is about people, a human history, these are not monsters, they are people who suffered and those who perpetrated and trying to understand who they were and what their ambitions are is fascinating the psychology," he says.
The researcher has also criticised western media for distorting the truth about the Genocide.
"It's hugely sad, as a British, that people are so ignorant and so driven by the worst motives on such an important and difficult subject so they are looking for headlines and readers. They don't understand the significance of (the terminologies about) genocide in the same way I would say the court in Arusha (ICTR) didn't understand the significance of the crime they have been trying.
Genocide is a crime like no other, the most hideous crime that can be committed. In the UK, I think journalists like conspiracy theories, people might watch. Unfortunately we live in fake news era and it sells, it goes against the orthodox and what we know, he said.
But in the case of genocide, Wallis said, you cannot just reinvent genocide because you want more views. "Some of it is just lazy journalism and no research done."
"What is also hugely depressing is that this never happened during the Holocaust," he adds, "that's a subject they know is off-limits because of the uproar that would happen and yet they can do that here because Rwanda is a small country and they think is not able to defend themselves."
"We see these double standards also in justice, there is no way the West could wait 10 years for criminals to get extradited, but the reverse is true, I'm very sad to note that the United Kingdom has ignored bringing justice to the survivors by putting to trial or extraditing those responsible."
Fighting genocide ideology, he says, is a lifelong battle, but also a generational battle because where there is a crime, so will denial.
"Denial is best fought by education and the truth being openly available to people in Rwanda and (abroad). I think it's happening here and maybe it's taken a few years but how precious are archives, witnesses and documents and every court throws this up but they stop the shifting science of denial," he says.