Circumstantial evidence often gets a bum rap in televised whodunits and other forms of popular culture. In real life, it's the best evidence there is, provided it's collected meticulously and properly interpreted. This presupposes diligent forensic work on the part of the police. That was precisely what the police vociferously crowed about last week, when they claimed an impressive series of interconnected gang-busting achievements. Their prodigious self-congratulation featured the boast that they had finally gotten the goods on two of the biggest-name local crime overlords - Amir Mulner and Ze'ev Rosenstein. Both happen to be behind bars anyway at present. Rosenstein, though convicted by an American court and sentenced to 12 years for drug trafficking, is doing his time here. Mulner is in custody for illegal firearm possession and conspiracy to commit crime. He has been convicted but not yet sentenced. Perhaps miffed because it took US cops to imprison Rosenstein, police spokesmen appeared to draw special satisfaction from announcing that they had a witness who had agreed to tie Rosenstein conclusively to the murders of a rival mobster and his two bodyguards in Tiberias in 2001. Mulner, for his part, was charged with collusion in a cocaine smuggling caper from Panama. Over 20 suspects have thus far been detained in the much-ballyhooed case. One of them was reportedly the witness who fingered Rosenstein. IMPEDING ANY narcotics importation is laudable. But the Panamanian connection was of mega-proportions, reportedly one of the largest in Israeli history. The fact that it was foiled means that 108 kilos of cocaine won't reach our streets. This was ensured via cooperation with Panamanian law-enforcement authorities, who raided a warehouse where the cocaine was stuffed into audio equipment awaiting shipment to Israel. Had the police made do with publicizing just this interception, its pretentiously-named "Operation Northern Star" would in itself have been recognized as a stellar success. The police would have emerged from this episode with deserved acclaim rather than egg on its face. However, the top brass - possibly hankering after good press at long last - got greedy and set out to bask in glory it hadn't quite earned. Before making certain it could translate suspicions - however well-founded - into proof and make the proof stick, it proudly declared that it had finally constructed decisive cases against both Mulner and Rosenstein. The police-orchestrated hoopla included effusive boasting from police Insp.-Gen. David Cohen for showing that "underworld bosses cannot escape the police's long arm. We have dealt them a huge blow." The more Cohen and his highest-ranking officers have overly aggrandized a respectable accomplishment, the more it has now been devalued. All charges against Mulner and Rosenstein arising from the Panamanian bust have had to be dropped humiliatingly, with the police forced to admit that they had nothing that could stand up in court. SADLY, THIS isn't an isolated episode of uninhibited and unjustified hubris on the part of our constabulary. Self-perpetuated hubbub notwithstanding, the battle the police wages against organized crime is no stunning success. The bombastically launched Lahav-443 anti-mob unit is in trouble. Its commander, Yoram Halevi, left his position after a mere nine months. He and a crucial colleague, Yoav Segalowitz, head of the Investigations and Intelligence Unit, weren't on speaking terms. This isn't helpful when going after the toughest crime syndicate kingpins. The police predilection is to rely on confessions rather than on the prolonged, arduous forensic work necessary to collect reliable circumstantial evidence. Certain offenders may be prevailed upon, even bullied, to confess, but certainly not consummate "professional" felons like Mulner and Rosenstein. If police are to defeat them, they must first internalize that they are not dealing with easily browbeaten small-fry. That top officers felt the need to blow their own horns, exulting in victories that were not yet won, signaled their desperation for a PR coup. The embarrassing result has also underlined that the police have yet to make the conceptual transition required in their fundamental approach to crime-busting if they are to prevail against sophisticated offenders and make us all safer.