A Canadian close to two countrymen implicated in an attack on a gas plant in Algeria that left dozens dead was detained in North Africa before the assault, public broadcaster CBC reported on Wednesday.
But the man's brother denied that he had been arrested, telling Global News he was in the region and had talked to him by phone on Sunday.
At least 38 hostages - 37 foreigners and one Algerian - and 29 militants were killed during a days-long siege and rescue operation by the Algerian army following the January 16 attack by jihadists on the In Amenas plant.
Citing "international intelligence sources", the Canadian Broadcasting Corporation said Aaron Yoon, aged about 24, left Canada last year with two former high school friends from London, Ontario - Xris Katsiroubas, who hails from a Greek Orthodox family but converted to Islam, and Ali Medlej.
Katsiroubas and Medlej died during the siege, possibly by blowing themselves up.
Yoon, who grew up Catholic but converted to Islam, was jailed before the attack, CBC reported, without mentioning where.
The group consisted of four individuals, CBC said, but the fate of the fourth is unclear.
But Yoon's brother, who reportedly spoke with two Global News journalists on condition of anonymity, denied the story, saying he had spoken with Yoon on Sunday.
"He's not in trouble," Yoon's brother told the broadcaster. "I believe him. I have no evidence otherwise."
The brother said he spoke with Yoon by phone on Sunday after being told by Canadian police that Katsiroubas and Medlej were dead.
"He was totally shocked. He didn't know that happened. He seemed genuine," he said.
According to the brother, Yoon is travelling in North Africa to learn Arabic and study the Koran, not engage in terrorist attacks - though he did meet up with his two old friends in the region prior to their deaths.
Commenting on Yoon's conversion to Islam, his brother said: "It was a positive thing. I obviously had questions, a few conversations about it... He was just a better person, much more respectful."
"It's because they were friends in London and met overseas, and he was [one of] the last people that Xris and Ali spoke with," the brother said. "He wasn't in the attack."