She said Toth entered Nicaragua with a false passport and also had a fake driver's license and credit cards.
Toth was being handed over to FBI agents present at the news conference and they planned to take him to the U.S. in a special plane, Granera said.
A thin and nervous-looking Toth dressed in cream-colored shirt and pants was briefly presented to journalists and photographers who took his picture, but he wasn't allowed to talk and was quickly taken away.
Granera said Toth first entered Nicaragua on Oct. 24, 2012, and left on Jan. 27. He returned on Feb. 12 and that's when Nicaraguan police began keeping a close watch, she said.
"He was captured in a house in the Panama Soberana neighborhood in Esteli, even though he resisted," Granera said.
Toth taught third grade at Beauvoir, a private elementary school on the grounds of the Washington National Cathedral. He was escorted off campus in June 2008 after another teacher reported finding sexually explicit photographs on a school camera in Toth's possession. He had not been seen since he lost his job.
In a statement, the school commended the work of U.S. authorities.
"We commend the work of the Office of the U.S. Attorney and the FBI for their ongoing efforts to apprehend Mr. Toth. They have been tenacious and resolute in their quest to bring this case to justice," it said.
Toth was added to the FBI's most-wanted list in April 2012 for allegedly possessing and producing child pornography, giving him notoriety normally reserved for people sought in connection with violent crimes or terrorism.
Osama bin Laden and purported Boston mobster James "Whitey" Bulger have both been featured on that list, but the FBI said it put Toth on because there were no reliable clues as to his whereabouts and because his Internet skills and alleged penchant for grooming children made him especially dangerous.
Authorities found Toth's car at the Minneapolis-St. Paul International Airport in August 2008 with a note suggesting he'd committed suicide in a nearby lake. But no body was found.
The FBI, which had been offering a $100,000 reward for information leading to Toth's arrest, said he was believed to have traveled to Virginia, Illinois, Indiana, Wisconsin and Minnesota. It said Toth is originally from Hammond, Indiana, and is a graduate of Purdue University.
Toth is thought to have lived in Arizona in 2009.
The bureau had said that Toth might have been advertising as a tutor or a male nanny and using the alias of David Bussone.
Associated Press writer Eric Tucker in Washington contributed to this report.