But they had suspected he might be since September, when Guccifer hijacked a personal email account used by Mr. Maior, the security chief, and then used it to send Romanian-language messages to Mr. Maior’s official email account at the Romanian Intelligence Service.
Mr. Maior promptly ordered an investigation. “It was clear he had broken into my email,” Mr. Maior said. “He wanted to prove something. I took it seriously.”
Aided by American investigators, who had been hunting in vain for Guccifer for months, the Romanians quickly homed in on Mr. Lazar, who had left a clumsy trail of clues.
“He made many mistakes,” Mr. Badea, the prosecutor, said.
Mr. Lazar said he could have covered his tracks better if he had had more money — for a more powerful computer, for instance.
“Of course, I could have stolen money from them,” he said, distancing himself from the legions of his countrymen who have made Romania, the second-poorest country in the 28-member European Union, a global leader in Internet fraud. “I didn’t. Not a single dollar.”
An American indictment filed against Mr. Lazar in Virginia in June accused him of trying to extort “money and property by means of materially false and fraudulent representations, pretenses and promises” to his American victims, but Romanian investigators say they found no evidence of extortion.
Romanian officials say the United States has not asked Romania to extradite Mr. Lazar but has sent investigators to question him to learn how he managed to prey on so many powerful Americans. The United States Justice Department declined to comment.
Before agreeing to answer questions from The New York Times in prison, where he shares a cell with four others, including two convicted murderers, he read out a lengthy handwritten statement that he said explained the purpose of his hacking.
A potpourri of conspiracy theories about the terrorist attacks of Sept. 11, 2001, the 1997 death of Princess Diana and alleged plans for a nuclear attack in Chicago in 2015, it said: “This world is run by a group of conspirators called the Council of Illuminati, very rich people, noble families, bankers and industrialists from the 19th and 20th century.”
Mr. Badea, the Romanian prosecutor, scoffed at Mr. Lazar’s fixation on so-called Illuminati as a ruse intended to give a political gloss to a peeping-tom hacking addiction. The hacking exploits that led to his 2011 conviction involved “no Illuminati, just famous and beautiful girls,” the prosecutor said.
Mr. Lazar denied any interest in celebrities, asserting that he had only stumbled on most of the people he hacked as Guccifer, a long list that included the actress Mariel Hemingway, the “Sex and the City” author Candace Bushnell, the editor Tina Brown, the comedian Steve Martin, the author Kitty Kelley and many others.
With no access to a computer in jail, he now pours out his phobias and conspiracy theories in notebooks filled with his small, neat handwriting. “O.K., I broke the law, but seven years in a maximum-security prison? I am not a murderer or a thief,” he said. “What I did was right, of course.”
