Survivors of January’s bloody siege at an Algerian gas plant paint a chilling picture of Xristos Katsiroubas, a Canadian jihadist killed during the raid that ended the standoff leaving at least 37 foreign hostages and 29 kidnappers dead.

In interviews with CBC News, several former hostages portrayed Katsiroubas, 22 — an Islamic convert who had been raised in a Greek Orthodox Christian home in London, Ont. — as a leader of the terrorist cell that captured the plant at In Amenas, Algeria on Jan. 16.

From the start, they said Katsiroubas stood out among the al-Qaida-linked group that took over the facility. He spoke fluent Arabic and English, conducting negotiations, and briefing jihadist associates over the telephone.

An Algerian worker identified as “Mohammed” who escaped on the second day of the four-day siege said he heard Katsiroubas providing what appeared to be a situation report on the phone.

He “was speaking in English, saying: ‘Everything went well; we have two groups,’ “ Mohammed said — apparently referring to the hostages.

Mohammed said he pretended not to understand English out of fear that Katsiroubas might try to enlist him as a translator.

After capturing the plant, Katsiroubas and the other militants went on a door-to-door hunt for foreign workers. As they found them, they bound their hands and feet. Some had their wrists bound by an explosive type of rope and some were required to wear explosives around their necks like a necklace.

Filipino technician Joseph Balmaceda was bound and remained close to Katsiroubas for much of his two days in captivity. He heard the Canadian on the phone demanding removal of Algerian troops that had surrounded the plant.

Balmaceda — the only hostage to survive an explosion in the truck he was transported in — heard Katsiroubas threaten to kill one hostage an hour if his troop-withdrawal demands were not met. Every so often, while the terrorist was on the phone, his colleagues would fire several rounds from their weapons for emphasis.

Katsiroubas once told a terrified Balmaceda that the threats were just a “bluff.”

But in reality, dozens of these foreign workers ultimately died at the hands of their jihadist captors — some in point-blank shootings, others while serving as human shields.

When Algerian helicopters approached the plant, Katsiroubas ordered hostages to stand in a circle and raise their hands. The hostages watched as he assembled what appeared to be improvised explosive devices right before them.

When a militant detonated one such device inside the vehicle he was riding in, Balmaceda  sandwiched between two spare tires miraculously survived.