It is the case of Curious Judge and The Man with the Yellow Hat.

A federal appeals court said it can be acceptable for a judge to conduct an Internet search to confirm an intuition about a matter of common knowledge.

While Monday's ruling by the U.S. Second Circuit Court of Appeals in New York concerned an alleged violation of the terms of supervised release from prison, the ruling could encourage more Internet use by judges, and not just in criminal cases.

The case concerned an Internet search performed by U.S. District Judge Denny Chin, whom President Barack Obama has nominated to fill a vacant seat on the Second Circuit.

Prosecutors alleged that Anthony Bari, who served 12 years in prison for bank robbery, violated terms of his release by robbing a Ridgewood Savings Bank branch in Bronx, New York.

Chin reviewed several pieces of evidence, including a bank surveillance video showing a robber who wore a yellow rain hat. A yellow rain hat was found in the garage of Bari's landlord.

Noting similarities between the hats, Chin at a hearing said he resorted to Google Inc's search engine for help. We did a Google search, and one can Google yellow rain hats and find lots of different yellow rain hats, he said.

Considering all of the evidence, Chin found the government met its burden of showing Bari violated his supervised release terms. He sentenced the defendant to three years in prison.

Bari appealed, saying Chin should not have gone online to verify a fact whose answer was not obvious. He said this violated a federal evidence rule that bars a presiding judge from testifying as a witness.

The government said the search was fine, citing another rule that lets judges note facts not subject to reasonable dispute and which can be learned from accurate sources.

In its decision, the appeals court said most federal evidence rules do not apply with their full force in proceedings to revoke supervised releases.

Using this relaxed standard, it endorsed Chin's effort to confirm his common sense supposition that more than one yellow rain hat is available for sale.

But it went further, saying improved broadband speeds and Internet search engines cut the cost of confirming intuitions.

The court said that 20 years ago. a trial judge may have needed to travel to a local department store to survey the rain hats on offer.

Today, however, a judge need only take a few moments to confirm his intuition by conducting a basic Internet search, it added. As the cost of confirming one's intuition decreases, we would expect to see more judges doing just that.

David Hammer, a lawyer for Bari, said he had yet to discuss the ruling with his client.

I'm surprised at the reasoning, which seems to authorize judges to use the Internet without any clear rules, Hammer said. As I read this, it could apply in any context where the normal rules of evidence are not strictly applied.

The case is U.S. v. Bari, U.S. Court of Appeals for the Second Circuit, No. 09-1074.

(Reporting by Jonathan Stempel; Editing by Tim Dobbyn)