One witness fails to show up in court after he is found lying unconscious in his apartment, surrounded by empty bottles of alcohol.

One witness fails to show up in court after he is found lying unconscious in his apartment, surrounded by empty bottles of alcohol.

Another mistakes a jailed Palestinian terrorist for a Libyan defendant in a photo lineup.

Yet another changes his story so many times that prosecutors distance themselves from him - inclined to agree with the defense that he was "mired completely in a web of deceit, cunning and lying."

With the first stage of the Lockerbie trial finished and the court in recess until Aug. 22, a cast of unreliable witnesses has left an impression that the prosecution case has been irreparably harmed.

Two Libyans are on trial at a special Scottish courthouse in the Netherlands for bombing Pan Am Flight 103 over Lockerbie, Scotland, on Dec. 21, 1988, killing 270 people.

Despite apparent weaknesses, many Scottish legal experts say the prosecution is developing a case that does not hinge on the testimony of questionable witnesses such as Swiss businessman Edwin Bollier.

Bollier's Zurich-based firm MEBO supplied explosive timers to Libya and the former East German secret police with links to terror groups, and may have supplied the equipment that went into the Lockerbie bomb.

But Bollier's weeklong testimony was so contradictory that even the prosecution challenged his credibility.

"Despite all the bluster of Bollier, nobody has sabotaged the Crown's (prosecution's) case," said Mark Mackarel, a lecturer in international criminal law at the University of Dundee.

Before going into recess, the court completed the opening stages of proceedings against the Libyans, who are charged with the murder of 259 people on the airliner and 11 Lockerbie residents. Prosecutors expect to wrap up their case in September. The defense case also is expected to last several months.

Defendants Abdel Basset Ali al-Megrahi and Lamen Khalifa Fhimah have pleaded innocent, blaming Palestinian terrorists operating in Germany at the time of the attack.

The strategy is to cast enough doubt on their culpability to win a dismissal, if not an acquittal.

According to the experts, hopes of conviction lie in the reams of forensic evidence and technical detail painstakingly gathered by investigators, scientists, and intelligence agents. Some 140 witnesses have appeared during the first 40 days of hearings.

Prosecutors claim Megrahi and Fhimah, who worked for Libyan Arab Airlines on the Mediterranean island of Malta, were really spies in the service of Libyan leader Moammar Gadhafi.

On the morning of the disaster, they allegedly placed a suitcase containing a plastic explosive onto an Air Malta jet, with so-called "interline" tags routing the bag on connecting flights through Frankfurt to London and onto the New York-bound jumbo jet.

Edinburgh University professor Robert Black, a critic of the prosecution's handling of the case, notes that no direct proof of the defendants' guilt has been presented.

"They haven't got anyone pointing and saying: 'We saw Megrahi or Fhimah or both of them manufacturing the bomb or putting a suitcase in the interline system to Frankfurt," said Black, a Lockerbie native who first suggested this neutral trial venue to Gadhafi back in 1994.

In recent weeks, problems with prosecution witnesses multiplied.

On July 12, hearings were canceled after a group of Maltese airport workers suddenly refused to testify for reasons that remain unclear. Prosecutors, who cannot compel non-Britons to testify, are trying to arrange a special hearing for them in a Maltese court.

On July 25, Frankfurt airport x-ray operator Kurt Maier who checked the interline bags to London on the day of the tragedy, couldn't appear, according to prosecutors, because an alcohol overdose left him in critical condition.

While other legal scholars agree that prosecutors have not yet satisfied the standard for proof of guilt under Scottish law, they downplayed the importance of the few muddled witnesses.

Prosecutors have a meticulously assembled case based on circumstantial evidence, which can be even more persuasive that one or two eyewitnesses - "when there's a lot of it," said Scots law of evidence specialist Fraser Davidson.

"You have combinations of evidence," said Clare Connelly of Glasgow University law school.

"You've got hotel stubs and visa stamps showing that the accused where in Malta at the relevant dates," she added. "You have got connections between the first accused (Megrahi) and MEBO and MEBO and Libya which haven't been denied."

Earlier this month, Maltese shopkeeper Toni Gauci hemmed and hawed as he candidly questioned his own recollections that Megrahi was the man who walked into his shop 12 years ago and purchased clothing found in the Samsonite suitcase.

Defense lawyers pointed out that when Gauci was presented with a lineup of photos and asked to identify Megrahi, the shopkeeper picked out Mohammed Abu Talb, an Egyptian-born Palestinian jailed in Sweden for terrorist bombings.

"I would be worried if someone after 12 years is absolutely certain," said Connelly. "His confusion, his lack of certainty, the openness of this man, seemed to be much more convincing."