Sven Olaf Kamphuis was arrested in Granollers for launching a massive denial of service cyberattack.

The orange Mercedes van caused quite a stir when it was parked up outside the Javis snackbar in Granollers, Barcelona province. Straight away bar owner Rafa was outside taking photos with his cellphone of the "solar panel and the two or three antennas" coming out of the roof. The owner of the van was no less eccentric-looking: a tall, scrawny, foreign-looking man who spent all day bringing computer towers, laptops and the like down from his apartment, on the third floor of number four Figueres street, to the van parked outside. It was impossible not to notice him and many locals opted to strike up a conversation with this oddball stranger. "Really nice van," said a group of youngsters, who went inside the vehicle on April 16.

"Yes, yes," the man replied.

From that moment Sven Olaf Kamphuis, 35, became known as "El Yes Yes" to everyone in Granollers. To the police, however, he was "the person responsible for launching the biggest denial of service cyberattack in history." On April 25 Javis's customers had a front-row seat for his arrest.

Back in March a denial of service (DoS) attack on the Swiss security firm Spamhaus slowed down internet access across Europe and the United States. Authorities believe the attack was initiated by Cyberbunker, a web-hosting company linked to Kamphuis, after Spamhaus included the company on its spam blacklist. It also added CB3ROB, an internet service provider that Kamphuis started at the age of 18.

After receiving a European arrest warrant from the Dutch authorities, Spanish police officers apprehended Kamphuis as he was returning to his apartment from a trip to the supermarket.

What are you doing? I am the Foreign Minister of the Cyberbunker Republic"

At 10am on Thursday, Paco from the local real estate agency ran over to the Javis. "There's a strange Volvo and a Seat León parked on the corner: I think they are undercover police," he told 26-year-old Rafa, who then kept watch to confirm that Paco was telling the truth. At noon, the Seat León moved to the parking lot of the nearby Dia supermarket, where Kamphuis had taken his orange van. At 1pm, the Volvo also disappeared. A short while later, a plain-clothes policewoman entered the Javis, went to the restroom, came out and walked to the street corner. She poked her head round, then returned at a brisk pace to the front door of the alleged hacker's building.

The Dutchman soon appeared round the corner carrying two bags of shopping from the supermarket. When he arrived at the door the woman held the door open for him and at that moment the other policeman ran towards the building and the Seat León reappeared, from which three more officers got out and also went into the hallway.

"What are you doing?" the Dutchman asked them. "I am the Foreign Minister of the Republic of Cyberbunker."

He asked for diplomatic treatment, say police sources, who are still not sure whether he was joking or not. "In any case, we didn't give it to him," explains chief inspector José Rodríguez of the information technology unit.

At 4pm they brought Kamphuis out handcuffed. Inside the penthouse apartment, they found a scooter, piles of boxes and papers, computers, antennas, cables and walkie-talkies... The bed was unmade and on the duvet was a copy of the book Quicksilver by science-fiction author Neal Stephenson.

According to the police, Kamphuis is a computer expert and activist who started his own internet service provider at the age of 18, continuing to work there to this day. He is a member of the Pirate Party, which defends free access to the internet and net neutrality - which is to say, that all internet information should be treated equally. He moved to Spain at the beginning of the year and signed a 12-month rental contract, even putting his full name on his mailbox.

"He never said hello to anyone on the stairs, and the lights were always turned on...," says a neighbor who lives on the first floor.

"He didn't bother anyone, but neither did he make an effort to socialize," adds a woman from the second floor.

For Kamphuis, real life was the computer. A few days before his arrest he was still going over the interviews he had given as the spokesman for Stophaus - a group of people fighting for internet freedom that claimed responsibility for the attack on Spamhaus - on Facebook. Kamphuis, however, denies any personal involvement in the attack. When he discovered that the investigation was pointing towards him, he told the UK's Daily Telegraph newspaper that he felt persecuted and compared himself with WikiLeaks founder Julian Assange.

The guys at Javis, who monitor everything that goes on in the street, had tried to win Kamphuis over and chat with him. "One day there was something about a German soccer team: we joked with him at the door but he said something we didn't understand," Rafa says. He never went inside the bar, not even to have a cup of coffee, and they never saw him with anyone else.

Now their oddball neighbor is a star in Granollers. "We did searches on YouTube and Facebook and saw that he gave TV interviews from the apartment," says Rafa's mother.

So why did an alleged hacker end up in Catalonia? "Because it is an attractive destination," chief inspector Rodríguez explains, referring to things such as the climate.

Kamphuis made no attempt to hide. He gave detailed accounts of his steps on the internet. In February he said he was in Spain and that a problem with his van had forced him to stop in Barcelona before continuing his journey to Málaga in his "mobile computing office."

He had even added a Spanish cellphone number to his Facebook page, which is open for anyone to see, and up until his arrest he appeared frequently in the media. His likes - he is in favor of the legalization of marijuana — and dislikes — authority, Luddites and Jews - are all over the internet. "I do have a problem with Zionists, not necessarily Jews in general, but Zionists, yes," he clarified in an interview with the website www.heavy.com. He also denied being homophobic. "I'm a homophobe? I'm gay. [...] As for homophobe, I don't know where they got that one from. I would say that there are a whole bunch of guys that don't agree with that view."

Authorities have dubbed the Spamhaus attack the biggest in history, but it is not an isolated incident. "Like in mobster movies there are groups on the internet who devote themselves to asking for money from companies in exchange for supposed protection. Their success resides in the fact that, on occasions, the cost of their services is less than that of a professional service, which is what annoys many and strengthens them," says Luis Corrons, head of security at Panda.

He says there is no way of measuring the scale of the attack. "In some regions it was hardly noticed," adds Eddy Willems, technical director at German internet security firm G Data, who for that reason plays down its importance.

Whether it was the biggest cyberattack in history or not, Kamphuis has been imprisoned since Saturday of last week under the orders of High Court Judge Santiago Pedraz, where he awaits his extradition to the Netherlands, which he has not opposed.

However, there's a part of him that will remain in Granollers: his orange van, which sits impounded by local police, waiting for someone to come along and fix it.