‘Nick was not just our brother, son and uncle, he was our best friend’ says family of Alexander, who was selling rock merchandise for Eagles of Death Metal

The poignant online search for loved ones began as soon as the world woke up to the news of the Paris attacks. Parisians, tourists and families scattered across the globe used social media to beg for information about those they feared had been caught up in the carnage.

In New York, Polina Buckley revived her dormant Twitter account in an attempt to find out what had happened to her British boyfriend, Nick Alexander. He had travelled to Paris as the merchandise seller for US rock band Eagles of Death Metal.

“Someone please help me find my boyfriend Nick Alexander #Bataclan #ParisAttacks,” she wrote. A few minutes afterwards, she posted a picture of a long-haired, bearded man smiling at the camera.

Others posted similarly heartbreaking pictures of children, parents, cousins, friends and lovers they desperately hoped were still alive.

“My friend Guillaume”; “my sister Soad”; “Valeria, an Italian” read some of the search notices multiplying under the hashtag #rechercheParis.

“Lucie Dira, 12 years old,” said one simply, above the pensive face of a pre-teen girl, one of the youngest missing.

Within a few hours of posting her message, Polina discovered that her boyfriend had been among the 89 people killed at the Bataclan concert hall when three terrorists forced their way into the venue and opened fire. When police stormed the building, one terrorist was shot but two managed to detonate suicide bombs.

On Saturday night Alexander’s family issued a statement confirming that the 36-year-old from Colchester had been killed – the first Briton to be named among the Paris dead. “It is with huge sorrow that we can confirm that our beloved Nick lost his life at the Bataclan last night,” the Alexander family’s statement said. “Nick was not just our brother, son and uncle, he was everyone’s best friend – generous, funny and fiercely loyal.

“Nick died doing the job he loved and we take great comfort in knowing how much he was cherished by his friends around the world.

“Thank you for your thoughts and respect for our family at this difficult time. Peace and light.”

Alexander had spent the evening with an ex-girlfriend, Helen Wilson, an American who runs a catering company in Paris called Rock en Bol. He had called her when the band arrived in Paris and they had spent the evening talking about old times. They heard noises outside the concert hall, then saw people running inside, Wilson told the Daily Telegraph.

“Maybe five, six guys came in with machine guns and shotguns and just started shooting people. It was mayhem,” she said. The couple lay down to avoid the bullets. “Nick was in front of me when we were lying on the ground and somebody moved and they just turned round and started shooting us.

“His back was to me and I couldn’t see what happened and I tried to keep him talking and then I tried to give him mouth-to-mouth resuscitation, and they [the gunmen] were just sort of in the shadows and they would shoot if anyone said anything.

“Then he couldn’t breathe any more and I held him in my arms and told him I loved him. He was the love of my life.”

As news spread that Alexander had been caught up in the Paris attacks, friends posted their own messages on social media. Joe Trohman, guitarist for rock band Fall Out Boy, tweeted: “Just found out Nick Alexander was one of the people murdered last night in Paris. Great guy. I’m horrified. #RIPNickAlexander”. Matthew Leone, the bass player for Madina Lake, said: “Nick Alexander was our @madinalake merch guy. Lived w us on & off the bus, through innumerable experiences. A treasured part of our family”.

A government source said that Alexander was not the only British casualty.

“We know of one death already. We fear there may be a handful of British fatalities, and about the same number are being treated for their injuries in hospital,” the source said.

Valentin Ribet, a lawyer, was among those frantically sought on Twitter by friends after he disappeared at the Bataclan concert. He was one of the first confirmed dead. “Our hearts are filled with sadness at this news,” the London School of Economics said on Twitter. Ribert had graduated from LSE in 2014.

The process of identifying victims was delayed because emergency services had focused first on rushing injured people to hospital, and had not began removing bodies until Saturday morning, French newspaper Libération said. In the chaos, many lost wallets and identification, or had left them in bags and coats in the cloakroom.

Other foreign governments have added to the grim catalogue of victims, with Belgium, Romania, Tunisia, Portugal, Spain, Sweden and the US saying their citizens had died in the attacks.

On Saturday night details of other victims at the Bataclan began to emerge. Nohemi Gonzalez, 23, was a junior at California State University, Long Beach, who had been studying abroad. Thomas Ayad, 32, an avid hockey fan, was a producer-manager for Mercury Music Group from Amiens in northern France. Alberto González Garrido, a 29-year-old engineer from Madrid, had gone to the concert with his wife but they were separated in the chaos. And Mathieu Hoche was a technician at the France 24 news channel. The 38-year-old was a passionate rock’n’roll fan, a friend said.

For Polina Buckley, one name on that list was the most devastating. She wrote: “You are and always will be the love of my life, Nick Alexander #fuckterrorism #ParisAttacks #Bataclan”.