Federal authorities yesterday charged an online advertiser in Florida with tapping into the computer system of a large database marketer in Arkansas and stealing "vast amounts of personal information" about Americans in what they described as one of the largest network intrusions in recent memory.

Prosecutors filed a 139-count indictment against Scott Levine, 45, of Boca Raton, in the Eastern District of Arkansas. Federal prosecutors say Levine exploited network links his company had to Acxiom Corp. in Little Rock and secretly downloaded millions of names, e-mail and home addresses and other details.

Levine was identified as the owner of Snipermail, an e-mail company that mailed out pitches for advertisers or their brokers. Acxiom, one of the world's largest data aggregators, has information about virtually every adult in America. It also manages and enhances data for major banks, insurers, direct marketers, the credit bureau TransUnion and others. It has developed some of the world's most sophisticated data analysis software, some of which it uses for homeland security screening for government contracts.

Yesterday's announcement came one year after authorities in Ohio discovered that a local man there, working for a company doing business with Acxiom, had illegally downloaded information from the Arkansas company. Acxiom discovered the second intrusion as it examined its computers for vulnerabilities following the discovery in Ohio. It brought the case to the attention of U.S. officials last year.

Since the thefts, company officials said they have upgraded security systems.

The indictment said that Levine gained access to Acxiom computers by misusing a legitimate password and user name while working for a company doing business with Acxiom.

Justice Department officials said they wanted to draw attention to the seriousness of computer security.

"The protection of personal information stored on our nation's computer systems is critical to public trust in those networks and to the health of our economy," said Christopher Wray, the assistant attorney general of the Justice Department's criminal division. "We will aggressively pursue those who steal private information from computer networks and make it clear there are serious consequences for such crimes."

Efforts to reach Levine by phone were unsuccessful.

Acxiom officials praised federal authorities for following through on the case and pledged to do a better job protecting the company's vast wealth of data about Americans. Among other details, the company keeps records on the value of individuals' homes, the type of work they do, the kind of cars they drive, their estimated income and the presence of children in their houses. "We are committed to safeguarding our systems and the data that we store and manage on behalf of our clients," the company said in a statement.

Prosecutor Sandra Cherry announces the indictment of Scott Levine on charges of stealing millions of names and addresses.