Google Inc executive Wael Ghonim, who was released in Cairo on Monday, said he was kept blindfolded for two weeks while being detained by Egyptian state security.
Google said last week that Ghonim, the firm's head of marketing for the Middle East and North Africa, had not been seen since January 27, two days after anti-government protests erupted in Egypt.
Ghonim said after his release that he was picked up by three plainclothes men in a street in Cairo, bundled into a car and taken off for interrogation by state security men.
He said he was blindfolded throughout his detention.
I am not a symbol or a hero or anything like that, but what happened to me is a crime, he told Dream TV.
If you want to arrest me, that's your right. But there are laws and I am not a terrorist or a drug-dealer. We have to tear down this system based on not being able to speak out.
Activists said Ghonim had been involved in founding We are all Khaled Said, an anti-torture Facebook group named after an activist who rights groups said was beaten to death by police in the port city of Alexandria. Two officers now face trial.
That Facebook group has been credited with sparking a public outcry over police torture and helping inspire the protests demanding an end to President Hosni Mubarak's 30 year rule.
Ghonim said he was not allowed any news on the protests nor was his family informed of his detention.
He said new Interior Minister Mahmoud Wagdy told him that the anti-government protests had taken the ruling party by surprise.
The (interior) minister said 'I've only been minister for seven days. You have achieved gains, and no one expected that. How did you do all that? All of us, those inside the party, inside the political system, were amazed, taken by surprise.'
Ghonim said Wagdy added: We couldn't understand what was happening. Now the situation is over. We won't go back again.
Google had launched a service to help Egyptians use Twitter despite government Internet restrictions by dialing a telephone number and leaving a voice mail that would then be sent on the online service.
(Additional reporting by Alexander Dziadosz and Jonathon Wright; writing by Shaimaa Fayed; editing by Edmund Blair)