At 10:58 on the morning of Aug. 5, 1977, the telephone rang in the Covington & Burling law offices of Richard D. Copaken in Washington.

"I've just returned from Germany," said an apparently British voice on the other end of the line, "and I understand you are looking for Nicky Artamonov."

That call from a man who identified himself only as "Benson" launched, a bizarre six-month odyssey for Copaken and for the wife of Nikolai Artamonov, also known as Nicholas George Shadrin, a Soviet defector who disappeared on an intelligence mission in Vienna on Dec. 20, 1975.

In the end, that search - inspired by what appears to be an intricate web of lies woven by a master con artist - would prove heartbreaking and expensive for Blanka Ewa Shadrin, who, according to Copaken, has spent his savings totaling $122,000 in search of her husband.

Strands of that web surfaced in a south London courtroom earlier this month where 44-year-old William Joseph Flynn was charged with obtaining money by deception and ordered held without bail for a trail to be staged sometime early next year.

In that morning telephone call in August 1977, "Benson" admitted that he was using a phony name for his own protection. But - according to a memorandum written later by Copaken - the caller had learned of the lawyer's search for Shadrin through an article the previous month in the international edition of Newsweek.

Identifying himself as a former British agent anxious to help find Shadrin, "Benson" suggested that Copaken place the following advertisement in the International Herald Tribune:

"Harry wants bank notes of 17th century origin" followed by the number of an unlisted telephone Copaken was to have installed in his office.

There was a "50-50 chance," said Benson, that a name named "Agnew" would see the advertisement and respond.

"Agnew" was a "mercenary character" said Benson, distastefully, but could help locate Shadrin since he had supplied the missing agent with false documents in Zurich six days after Shadrin disappeared in Vienna.

Benson warned Copaken that Agnew would probably hang up since Benson could not provide Copaken with the rest of the coded phrase that would assure Agnew that the advertisement was not a Central Intelligence Agency trap.

"If he believes you are with the CIA he will have nothing further to do with you," Benson warned. However, to prove his bona fides, Copaken was to tell Agnew that "the man that gave you his name is the same man he once gave a bottle of vodka to with a little plant growing out of it some years ago."

Something in that telephone call, according to Copaken, "was of riveting significance" to the Shadrin case. Although it does not appear to surface in Copaken's memorandum of the conversation, Benson made allusions "to things that could have been known only to Mr. and Mrs. Shadrin and to the CIA," according to Copaken, who will not further elaborate.

Copaken's relations with the CIA since taking on the Shadrin case six weeks after the defector's disappearance have been tenuous at best. Aggressive - and some say even abrasive - Copaken had placed himself squarely on the back of CIA officialdom. Typically, he ignored their advice not to and placed the ad on Sept. 15.

At mid-morning that same day his specially installed white telephone rang.

"Hello, Harry," said a voice on the other end. Copaken says he hurriedly tried to identify himself through the sprig-laden bottle of vodka. Th phone went dead.

"I thought I'd blown it," says Copaken.

But if in fact this was a fraud, it had a master's touch. At 9:58 the next morning Copaken's white telephone rang again, this time with a call from St. Jean-Cap Ferrat in the South of France.

On the line was the elusive Agnew who confirmed that he had supplied Shadrin with travel documents, that Shadrin was "alive, safe and well" and living in a Western country. Agnew would contact Shadrin and get back to Copaken.

Four days later, Agnew called again - this time from Beauleau sur Mer, a resort town just a few minutes from St. Jean-Capferrat.

Agnew had "been in touch" with Shadrin who was anxious to return to his wife, but feared reprisal from the CIA. He had asked Agnew to arrange for him to be able to speak with his wife by telephone.

Agnew had decided that the call was to be placed from a Buffalo, N.Y., hotel. The following weekend, after Agnew called Copaken at home with a one-word code - the name of the hotel - Copaken and Mrs. Shadrin were to leave Washington, to go to any other city in the United States, and they fly to Buffalo.

Once in Buffalo, Copaken would receive a call from a Mr. Putz - Agnew's bodyguard. Putz would meet them and search them for weapons and hidden tape recorders. Only then would they be delivered to Agnew in another part of Buffalo. The call to Shadrin would be made from there.

Agnew would need $3,000 for expenses to be cabled to the National Bank of Paris in Monaco under the name "W. Flynn."

Incidentally, he said, "the silly Englishman" (Benson) had been mistaken about the bottle of vodka. It has been Shadrin who had given Agnew the vodka.

Copaken wired the $3,000 as instructed. "I was suspicious," he says. "But Benson's information was incredibly accurate. I reasoned that the mathematical probability of his coming up with that story was about 1 in 120 million."

One week later, on Sept. 26, Copaken's special phone rang again. This time is was a furious Agnew demanding to know why Copaken had blown his cover. The Buffalo operation had to be scrubbed. Agnew would get back to him.

Six weeks later, when no further calls had come, Copaken decided that he had been swindled. He was nonetheless, haunted by Benson's flawless knowledge of "deeply personal" information known only to the Shadrins and to the CIA.

Could Benson and Agnew be one and the same person? If so, could Benson/Agnew be a CIA-inspired version to get the aggressive Copaken off the back of the CIA?

On Nov. 6, Copaken and Mrs. Shadrin flew to Monaco. They they discovered that the $3,000 had been picked up by "W. Flynn" who identified himself to authorities through an Australian passport issued in August 1975. He had given his local address as the yacht "Kasmit" anchored at Antibes.

No such yacht existed in the records of the Antibes harbor police. "W. Flynn," it developed, had obtained his passport illegally by furnishing Australian passport officials with birth records belonging to a Melbourne train conductor.

Why should Australian passport officials be suspicous - "W. J. Flynn," after all, was well known in Australia as a multimillionaire land developer, Gold Coast playboy, and incredibly, the owner of a luxurious yacht aptly name "The Goldfinger."

The Flynn who stood in a London dock two weeks ago was, in fact, the man the Australian press had once dubbed "Goldfinger" before he mysteriously disappeared on the phony passport, leaving behind a trial of allegedly unpaid debts totaling a reported million dollars.

Copaken could have known none of those details when, with the help of the French police, he finally tracked Flynn to another yacht called the "Rodi's Island" anchored at Beauleau sur Mer. On board with Flynn was a women identified later as Karen Steadman whose brother had recently been convicted of selling Royal Air Force secrets to the Soviets.

Did Flynn indeed have contacts in the murky world of the international spy trade network?

For the moment, Flynn admitted to Copaken only that he had been a messenger for Agnew. If Copaken would pay his way to London he would gladly take a lie detector test to prove it.

Sometimes," he told Copaken, "you need a small key to open a small lock. A large key won't work.

To help prove that he was that small key, Flynn proceeded to lay out a spy's treasure of documents for Copaken to examine, among them a small black memo book.

On the first page was the unlisted London telephone number of Palestine Liberation Organization leader Said Hammami - 629-0732. A month later, Hammami was shot dead in his office.

Scotland Yard sources have since confirmed the authenticity of a number of other international terrorists listed in Joe Flynn's little black book.

Flynn, indeed appeared to Copaken to be a man of many parts - most of them "scary as hell."

But Flynn had an admission to make. He had learned that "Agnew" and "Benson" were phony names. The real Agnew, Flynn claimed, was a superspy named Erik Muller, famed in the Bondian world of international spies for providing getaway documents for Ronald Biggs - the alleged brains behind Britain's Great Train Robbery.

But apparently no amount of documents or carefully devised explanations as to the mysterious Agnew and Benson could help Flynn stand up to the electronic probing of the lie detector in London.

On Dec. 13 he failed it "conclusively" in the words of the polygraph expert who administered it.

A discouraged Copaken flew home with an even more discouraged Mrs. Shadrin.

But the irrepressible Flynn was not to be discourage. Two weeks after failing his test (I even lied about my name," he later boasted to Copaken) he called Copaken again; if the lawyer would only fly to Vienna at Christmastime he would meet Erik Muller and Muller would produce Shadrin. Flynn needed $2,500 to help - but he would waive the money if only Copaken would help him an American green landing card.

Copaken was not buying. Still, the awful possibility that he was closing the door on any chance of finding Shadrin gnawed at him, he says.

Copaken decided that he would try one final test: if Flynn could provide the answers to three questions he would pay the money:

The true identity of Benson"

Shadrin's whereabouts when "Agnew" (now alias Muller) contacted him about the Buffalo rendezvous?

Ways to find Muller?

At a London meeting three weeks later. Flynn provided answers: "Benson" was a man named Michael Smallwood Thomas Blick: Shadrin had been reached in Rio de Janeiro; Muller could be reached through LLoyd's Bank in Monaco.

Copaken paid Flynn $1,250 - the balance to be paid and if the story checked out.

It never did: Blick turned out to be a British diplomat serving in Papua New Guinea; Erik Muller - who testified in London that he had never met Flynn in his life - is an international businessman and escort to the Crown princess of Denmark during her frequent visits to Monaco.

And Shadrin's whereabout are still a mystery.

The final act in this drama may be played out in the Old Bailey court in London. Meanwhile Flynn faces 10 years in prison and is being held without bond.

Scotland Yard sources have identified him as Barry Edward Gray, 43, born, they say, in a London slum. But another source says even Scotland Yard is not sure of all this.

Nor are observers of the trial certain Flynn will be convicted. Quite the opposite. They feel that the crown will not be able to persuade the British jury that Flynn is anything but the victim of another CIA plot. They expect acquittal, followed by a bidding war for the rights to Flynn's story.

Says one British journalist: "He'll be a bloody millionaire."