LOS ANGELES – Two Europeans were indicted Thursday for allegedly launching Internet attacks to shut down two retail Web sites in the U.S. – an attack that prosecutors believe was ordered by the retailers' competitor.

A federal grand jury indicted Lee Graham Walker of England and Axel Gembe of Germany on charges of conspiracy and intentionally damaging computer networks that belonged to Miami-based Rapid Satellite and Los Angeles-based Weaknees. The companies sell DVRs and television satellite systems.

The men, who remain at large, allegedly launched a distributed denial-of-service attack against the two Web sites on behalf of a competitor, Sudbury, Mass.-based Orbit Communications, prosecutors said. Such an attack involves a set of computers targeting a single online network, causing users and customers to experience error messages.

The two companies' Web sites were shut down for two weeks due to the attacks in October 2003, said U.S. attorney's spokesman Thom Mrozek. Weaknees lost more than $200,000 because of the security problem, Mrozek said.

The indictment is related to another case filed in 2004 against Jay Echouafni and Paul Ashley, who were also charged with conspiracy relating to the same computer attack.

Ashley pleaded guilty and served two years in prison in Ohio. Echouafni, who owned Orbit Communications, is a fugitive sought by the FBI.

The indictment said Echouafni and Ashley hired Walker to launch the distributed denial-of-service attacks on Orbit's competitors. Walker allegedly used a network he developed with Gembe.

Gembe wrote the first version of a computer worm called Agobot, a network of software robots that requires little computer programming knowledge to use, Mrozek said.

If convicted, Walker and Gembe face 15 years in prison.