BERLIN, Jan. 25 - Advice to art thieves: never get angry and depart from the plan. In particular, don't use a new cellphone to send a message to the police. It may prove your undoing.

Or, at least, that was the downfall of Robert Mang, a 50-year-old specialist in security-alarm systems who in 2003 pulled off one of the biggest art heists in recent years: the removal of the "Saliera" (or saltcellar), a rare gold-plated sculpture by Benvenuto Cellini, from the Kunsthistorisches Museum in Vienna.

After holding the Cellini masterpiece, valued at roughly $60 million, for nearly three years and making two attempts to collect about $12 million in ransom, Mr. Mang was identified as the culprit late last week. On Friday, the police had circulated security camera images of him buying a cellphone that he used to send a text message.

On Saturday, after the photographs appeared on television and in newspapers, Mr. Mang, described by police as a successful businessman with no financial problems and no criminal record, turned himself in. On Sunday, he led the police to a wooded area about 50 miles northeast of Vienna where he had buried the legendary 10 inch-high sculpture inside a lead box.

On Monday, the object was returned to the Kunsthistorisches, where it is scheduled to go back on display on Sunday. The object itself, a royal saltcellar dominated by gold-plated images of Ceres, the goddess of agriculture, and Neptune, the god of the sea, was sculptured by Cellini between 1540 and 1543 on commission from Francis I of France. It is the only fully authenticated work in gold by Cellini. "I am very happy," said Wilfried Seipel, the museum director, in a telephone interview from Vienna. "We have the 'Saliera' back after 1,000 days."

Countering speculation that the sculpture had been seriously damaged, Mr. Seipel said it was in good condition, with just a few scratches apparently caused when Mr. Mang broke its glass display case during the robbery.

Last fall, while bargaining unsuccessfully for a ransom for the sculpture, Mr. Mang removed a small trident from the Neptune's hand, sending police officers to a spot in a Vienna park where he had hidden it. But that caused no damage, Mr. Seipel said, because the trident was a separate piece unattached to the rest.

"I think we will not repair the scratches," Mr. Seipel said. "They are now part of the history of the object, and they do not affect its appearance."

But while the recovery of one of the most valuable artworks in Vienna's enormous collections had a happy ending, the heist itself set off a three-year nightmare for Mr. Seipel and others at the Kunsthistoriches, or Art History, Museum, who were accused by the Austrian press of lax security.

At one point during the saga, Mr. Seipel embarked on a wild-goose chase in Italy engineered by someone claiming to be the thief. The hoaxer said he was fatally ill and wanted to return the Cellini work before he died.

The art robbery took place in the early hours of May 11, 2003, when Mr. Mang climbed a scaffolding that had been built around the museum while its facade was being sandblasted and broke in through a second-floor window. Police officials said he had first seen the sculpture while on a guided tour of the museum, but their accounts of how he decided to steal it differ. In one account, he noticed the scaffolding around the museum and, having had a bit too much to drink, decided to climb up and steal the Cellini. But others, including Mr. Seipel, say that the job was well planned and could not have been pulled off on the spur of the moment.

When Mr. Mang entered the gallery where the Cellini sculpture was kept, he set off a movement-detection alarm. For reasons that have never been explained, the security guard on duty simply turned off the alarm and failed to investigate, Mr. Seipel said. If the guard had followed normal procedure, the museum director said, he would have turned on lights inside the building to allow video cameras to record whatever was taking place.

"If he had switched on the lights, maybe we would have never lost the 'Saliera,' because the thief would have found himself caught in the flare and maybe he would have just run away." Mr. Mang smashed the glass case holding the Cellini and escaped with it, apparently through the window and down the scaffold.

Ernst Geiger, the Austrian police inspector in charge of the case, has been quoted in news reports as saying that because of his expertise in alarm systems, Mr. Mang knew he had enough time to get away before he would be caught. But Mr. Seipel said the crucial ingredient in Mr. Mang's success was "a sleepy security guard who didn't do his duty."

For about two years, Mr. Mang, who was divorced and lived alone, kept the sculpture under his bed in his Vienna apartment, continuing his life as a security-alarm salesman. Then, in October, Mr. Geiger said, he contacted the company that had insured the sculpture and demanded 10 million euros for the return of the work. He provided Neptune's trident to prove that he indeed had the sculpture in his possession.

A week later he ordered that this sum be prepared as a ransom, sending a message in which he gave instructions for its delivery. He wrote that a single unaccompanied person should take the money on a bicycle to a certain point in Vienna where instructions would be sent by cellphone where to go next.

Mr. Mang used several different cellphones to send instructions during what the Austrian police have called a scavenger hunt that unfolded on that day, Nov. 7. To avoid being traced, he used each cellphone only once, Mr. Geiger said. He had purchased all the cellphones months or even years before, the police inspector added. But after several hours, Mr. Geiger said, Mr. Mang thought he saw some unmarked police cars at one of the points on the bicyclist's route. Irritated by what he saw as the flouting of his instructions, he used a recently purchased cellphone to call off the whole operation, Mr. Geiger said.

"Thanks for your efforts," his Short Message Service (or S.M.S.) ran. "We will get back to you shortly." Mr. Geiger said, "He got angry, and he made a mistake."

The cellphone was traced to a store on a major Vienna shopping street, which uses a hidden video camera to record all purchases. This enabled the police to obtain a picture of Mr. Mang, which they made public on Friday. That very day, Mr. Mang contacted the police to identify himself as the man in the picture but to deny that he was the thief.

"He called us Friday night and was upset about his picture, telling us we should make sure it wouldn't be published anymore," Mr. Geiger said. "We started to do some research. In his apartment we found notes about the scavenger hunt that he did with us. That was his doom."