The brother of one of the hostages killed in Algeria said he learnt of his brother's death on Facebook.
Kenneth Whiteside was executed by terrorists when Algerian security forces attacked the remote In Amenas complex gas complex.
Many hostages are believed to have been killed when Algerian forces attacked the terrorists at the In Amenas gas plant
Mr Whiteside, a 59-year-old from Glenrothes, Fife, who lived in Johannesburg with his wife and two daughters, was a planning manager at the In Amenas desert complex.
His brother said that police have confirmed he was executed.
Bob Whiteside, who lives in Crieff, Perthshire, told how he had learnt of his brother's death at the hands of Islamist terrorists from social networking site Facebook.
He told BBC Radio 4's The World At One programme: "We know now what's happened to Kenny but we actually had to find out for ourselves.
"We were not given any official information and it was through Facebook, of all things, that we found out of Kenny's demise.
"It was my daughter who found it on Facebook, a message from an Algerian co-worker.
"The police came last night and informed us that what was on Facebook was true, that Kenny had been... he was executed."
Peter Hunter, who was reunited with his wife, Kerry, on Monday paid tribute to Mr Whiteside and another Scot colleague, Carson Bilsland.
"I used to see Carson every morning and every lunchtime and we always had a bit of banter. He was a lovely guy, they all were," Mr Hunter said.
"Kenny Whiteside used to play the bagpipes. Occasionally he would have his kilt on. I used to sit on the step there and he used to say, 'I do requests'. He was a lovely, lovely man.
"It's just very sad."
Mr Bilsland, from Perthsire, is also believed to have died in the siege. He had reportedly worked in Algeria for around two years as a testing technician and was a former member of the British speed ski team.
A spokesman for the team described it as "a very sad day".
He said: "Carson was one of life's indomitable characters. He will be sorely missed but very fondly remembered."
A statement was posted on the British speed ski team's Facebook page but was later taken down at the request of Mr Bilsland's family, it said.
Scotland's justice secretary said those involved in the crisis had been through a "horrendous ordeal".
He said: "As the victims who have survived come home, they will be in contact to see what counselling can be provided because even those who have survived have been through a horrendous ordeal, as we have seen on the television, and we will be making sure, through police and other agencies, that appropriate contact is provided."
BP employee Alan Wright, 37, from Portsoy in Aberdeenshire, is among one of the survivors to have returned to the UK.
He was working at the plant when the Islamist terrorists stormed the compound.
The father-of-two hid in an office for 24 hours before joining Algerian colleagues in cutting their way through a fence and fleeing.
He told Sky News: "If you have been captured, there's pretty much no escape and it is going to take a miracle to get you out.
"The first cut of the fence, the wire and tension makes such a noise when it breaks and you knew it travelled to where the terrorists were.
"But within 30 seconds they had both fences open and we were free to go, that was it."
The siege is believed to have claimed the lives of six British nationals and one foreign-born UK resident.
Prime minister David Cameron said Britain will provide intelligence and counter-terrorism assets to help dismantle the terror network responsible for the attack.
Mr Cameron said that the world was involved in a "generational struggle" against al Qaida-inspired Islamist terrorism in North Africa, and vowed to show "iron resolve" in his response to the challenge.
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