LOS ANGELES — A Romanian man already convicted in his home country of hacking into NASA computers at the the Jet Propulsion Laboratory in La Canada Flintridge has been indicted in the United States, officials announced Wednesday.

Robert Butkya, 25, of Cluj-Napoca, Romania, was indicted by a federal grand jury on allegations of unauthorized impairment of a protected computer, U.S. Department of Justice officials said in a written statement. The alleged hacking took place in December.

Butkya used the moniker “Iceman” as he hacked into, and placed malicious software on, 25 computers that were part of NASA’s “Atmospheric Infrared Sounder Program — designed to support climate research and improve weather forecasting capabilities — in December, according to the DOJ.

In at least one instance, “He used the computers to launch attacks against other computers,” Assistant U.S. Attorney Erik Silber, who is prosecuting the American case, said.

It was not believed Butkya was trying to steal information from the system, Silber added.

In many cases, he said, the principal motivation of hackers is pride — to show off their prowess at accessing restricted systems.

“As a result of Butkya’s alleged conduct, researchers were unable to use the computers for more than two months while NASA removed the malicious code in the machines, restored data and took steps to prevent further access by hackers,” according to the statement. “NASA sustained more than $500,000 in damages, which includes the costs of completing the work on the computers and the time lost to scientific researchers.”

A Romanian court has already tried and convicted Butkya, sentencing him to three years in prison and seven years of probation, officials said.

Once he’s released from Romanian prison, he will have to be brought before a judge in the U.S. for the case to process, Silber explained.

Since Romania will not extradite in such a case, he said, prosecution in the United States will depend on with Butkya coming to America voluntarily, or being arrested in another country that will extradite him.

“As a practical matter, he has to come to the United States (to face trial),” Silber said.

If convicted in the U.S., Butkya faces up to 10 years in federal prison.