Some paint him as a reckless man who boasted about driving his Spanish trains at massive speed, before crashing one, leaving 78 people dead and 178 injured.
Francisco Jose Garzon Amo's friends and neighbours tell a different story.
The grey-haired driver has not appeared in public since he was helped to stagger, with blood pouring down his face, away from the wreck near the northwestern city of Santiago de Compostela on Wednesday night.
But, detained by the police, he has become the focus of speculation as a nation in mourning seeks to explain what caused its worst train disaster in nearly 70 years.
"He is an excellent professional. It is the first accident he has ever had," said Antonio Rodriguez, who joined the state rail company Renfe alongside Garzon in 1982.
The two started out as young auxiliary workers refuelling the trains in Monforte de Lemos, a small town in a green valley an hour and half's drive from Santiago.
Rodriguez is now the Galicia region railway workers' leader of the UGT, Spain's biggest labour union, and one of the relatively few individuals to defend Garzon publicly as authorities investigate.
"He has never been sanctioned in all the time he has worked since 1982," Rodriguez told AFP by telephone, his voice weary after days trying to contact his friend.
Media have widely cited a post the driver reportedly made on his Facebook page — since taken offline — with a photograph of a speed dial in a train showing 200 kilometres an hour (124 miles per hour).
Along with comments he reportedly made by radio immediately before the crash, the Facebook post has painted a compromising picture of Garzon.
El Pais newspaper cited sources in the investigation saying he told controllers that the train was going at 190 kilometres per hour. The curving stretch of track where it hurtled off the rails had a speed limit of 80 kph.
Newspapers have also quoted him as telling a control centre immediately after the accident: "I hope no one died because it will weigh on my conscience."
Interior Minister Jorge Fernandez Diaz said Saturday that Garzon was suspected of "reckless homicide".
Police said the driver refused to answer their questions in hospital and that it was now for the judges to decide whether to bring charges.
Garzon was discharged from hospital on Saturday and taken to a police station. He was due to appear before a judge on Sunday who will decide whether
to press formal charges, the interior minister said.
The head of the state firm ADIF which runs Spain's railway infrastructure, Gonzalo Ferre, has cast the blame directly on Garzon, saying he should have braked well before the bend outside Santiago.
That part of the track was not equipped, as many high-speed lines are, with the latest braking technology that would slow the train down automatically if the driver failed to so when required.
In the train station of Montforte de Lemos, workers shook their heads,grim-faced, when asked about Garzon. "All we can say about him are good things," said one person who knew the driver.
"It is a shame the things some people have said. But we cannot say anything," for fear of being misrepresented, he told AFP.
Garzon became a fully qualified driver in 2003. In the process, he left Montforte and worked out of several other cities before moving back to Galicia in 2011, to A Coruna, to look after his ageing mother, Rodriguez said.
Locals defended Garzon against unfavourable media speculation.
"People here are keeping quiet about it because it is a very delicate topic. But since he was born here, we are his defenders," said Jesus Asper, 54, sitting in the waiting room at Monforte station.
"Before becoming a train driver, he was an auxiliary labourer here. People say he was very responsible and very competent," he said, as he sat exchanging
theories about the crash with his friend Luis, 80.
"People want a spectacle. When something like this happens, they want someone to feed on."