Authorities in America have charged an 18-year-old youth with spreading the crippling MSBlast internet virus.
Parson has been placed under house arrest
Jeffrey Lee Parson of Hopkins, Minnesota, is accused of "intentionally causing and attempting to cause damage to a protected computer".
The teenager is suspected of releasing a variant of the so-called MSBlast worm, infecting hundreds of thousands of computers worldwide and causing them to crash.
If found guilty, Mr Parson faces up to 10 years in prison and a $250,000 fine.
Mr Parson is not believed to be the creator of the original MSBlast worm, also known as Lovsan.
Authorities said they are still investigating who invented the virus.
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John McKay, the public prosecutor in Seattle, said Mr Parson's arrest was a "significant step forward" in the hunt for the original culprit.
"The Department of Justice takes these crimes very seriously. We will devote all available resources to tracking down those who attack our technological infrastructure," Mr McKay told a press conference.
Investigators searched Mr Parson's home on 19 August and removed seven computers for analysis.
Mr Parson has been placed under house arrest in Minnesota without access to the internet.
All the MSBlast variants took advantage of a flaw in Microsoft Windows software which had been known about since mid-July.
Unlike many recent viruses, the worm travelled around by itself, exploiting a bug in the way that many versions of Microsoft Windows handled the transfer of files across the net.
When a computer was infected, it started looking for other machines to infect - usually on the small section of the net that the host PC was using.
"Once a virus has been released on the internet it can never be taken back, it is no longer under anybody's control and can be very damaging," said Graham Cluley, senior technology consultant at Sophos Anti-Virus.
At its height the virus was only taking 30 seconds to find uninfected machines, swamping computer networks.
Anti-virus firm Symantec estimated that more than 500,000 computers worldwide were infected by the worm and its variants.
Several large organisations, as well as many home users, were caught out by the virus.