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The dispute was about ancient history. But the tactics someone used to cast aspersions on a prominent Judaic studies scholar couldn't have been more modern.

New York University professor Lawrence Schiffman's students and colleagues started getting panicked and confessional e-mails, in his name, that pointed them to blog posts accusing him of plagiarism. Prosecutors say the e-mails and website posts were a hoax created by a lawyer on an idiosyncratic mission: to champion his father and discredit Schiffman in a debate over the origin of the Dead Sea Scrolls.

The attorney, Raphael Golb, went on trial Tuesday on criminal charges of online impersonation and harassment for the sheer sake of coloring opinion. The case is a rarity: While impersonation claims have generated civil lawsuits, prosecutions are few unless phony identities are used to steal money, experts say.

Golb, 50, has pleaded not guilty to identity theft, criminal impersonation and other charges. He hasn't acknowledged crafting the messages, but his lawyers say the plagiarism allegations are true, and the writings amount to typical blogosphere banter — not crime.

Manhattan prosecutors say Golb mounted an elaborate, carefully cloaked effort to promote his father's side in a rarefied but vigorous scholarly dispute over which ancient Jews wrote the more than 2,000-year-old scrolls. Found in the 1940s in Israel, the scrolls include the earliest known version of portions of the Hebrew Bible and have shed important light on Judaism and the beginnings of Christianity.

Many scholars say the scrolls were assembled by a sect known as the Essenes. Others — including University of Chicago professor Norman Golb, Raphael Golb's father — say the writings were the work of a range of Jewish groups and communities.

Schiffman told a Manhattan jury Tuesday that he and Norman Golb have long disagreed, albeit cordially, about the issue.

But prosecutors say the argument so angered Raphael Golb that he crossed the line from commentary into crime by crafting the blog posts and e-mails to tarnish Schiffman.

The posts, written under various names, accused Schiffman of stealing from Norman Golb's scholarship. Schiffman denies it and says the material in question is common knowledge.

The e-mails, which appeared to come from Schiffman, asked the recipients to help cover up the supposed plagiarism: "This is my career at stake," read some.

Assistant District Attorney John Bandler called the electronic whisper campaign "a disturbing pattern of conduct," involving about 70 phony e-mail accounts and hundreds, if not thousands, of hours of work. Schiffman said he devoted weeks responding to inquiries from colleagues, students and NYU officials.

"I was beginning to feel myself in a very attacked position," he testified.

But one of Golb's lawyers, David Breitbart, told jurors Monday that he would show the plagiarism allegations were valid — and made in the spirit of satire.

"The representations that are made are never rude, are never impolite. They never attack," he said in an opening statement. "You're going to find that they fall into the category of parody."

Still, he added: "it's not going to be an easy case. ... There are going to be some difficult questions."

Indeed, Tuesday's testimony touched on topics ranging from the Roman thinker Pliny the Elder to the ancient Jewish desert fortress of Masada. And that was before lunch.

Financial frauds accounted for the vast majority of the more than 336,000 complaints made last year to the Internet Crime Complaint Center, run by the FBI and the nonprofit National White Collar Crime Center. But some states are trying to crack down on Internet impersonation; California lawmakers this summer passed a measure that would make "e-personation" a misdemeanor.

Still, criminal prosecutions have been relatively rare when no financial crimes are involved, partly because it can be tough to establish legally what harm a victim suffered, said Bennet G. Kelley, a Santa Monica, Calif., attorney who specializes in Internet law.

"The first question you have to look at is harm ... and once you have that, you have to figure out: Is there First Amendment protection here?" he said.

In one high-profile example, Missouri mother Lori Drew was accused of helping her daughter and a friend pose as a teen boy on MySpace to send hurtful messages to a 13-year-old neighbor girl. The girl committed suicide.

A federal jury in California, where MySpace has its servers, convicted Drew of misdemeanor counts of accessing computers without authorization. A judge overturned the verdict and acquitted her.

Other online-alias cases have cropped up in civil courts. St. Louis Cardinals manager Tony La Russa sued Twitter last year over an unauthorized account in his name, saying it caused him emotional distress by making light of such things as the deaths of two Cardinals pitchers. He dropped the case last year.

In an ongoing case, a former model turned business consultant filed a lawsuit last month asking a court to force YouTube and owner Google Inc. to reveal the identity of a person who posted what she said were unauthorized videos of her and online comments that damaged her reputation. Google has said it follows applicable laws but won't discuss individual cases to protect users' privacy.