A photograph released by the law firm Carter-Ruck, Jan. 21, 2014 shows an individual with a belt-like object around his neck. The photo is part of a report alleging the systematic torture of Syrians under the Assad regime. Carter-Ruck/EPA

The photographs show emaciated bodies marked with signs of brutal beatings, strangulation and other forms of torture, the team confirmed.

"This is a smoking gun," David Crane, one of the report's authors, told CNN. "Any prosecutor would like this kind of evidence — the photos and the process. This is direct evidence of the regime's killing machine."

The report also details a complex numbering system used to catalog the corpses such that security services could keep track of those killed and fake their documentation to make it appear that the individual had died in a hospital.

"This evidence could underpin a charge of crimes against humanity — without any shadow of a doubt," said Desmond de Silva, another of the authors and the former chief prosecutor of the Special Court for Sierra Leone, in an interview with CNN. "Of course, it's not for us to make a decision. All we can do is evaluate the evidence and say this evidence is capable of being accepted by a tribunal as genuine."

Both sides of the conflict have been accused of human rights violations on many occasions during Syria's nearly three-year civil war, but the experts believe this new round of evidence is the most definitive proof of large-scale killing on the part of the regime to date.

The authors added that the scope and systematic nature of the killings indicates "top-down" direction by leaders of the security forces but not the direct involvement of the Syrian President Bashar al-Assad himself.

Al Jazeera