INDONESIA - Most drug cases remain unsolved because police officers cannot resist the temptation to use the evidence, an expert says.

"How can we clean a dirty floor if the broom is also dirty?" said Adrianus Meliala, a criminology professor at the University of Indonesia in Depok.

Many police officers begin to use drugs when they are investigating drug-related crimes, he said. The investigation process requires them to frequently meet with criminals and drug users as well as visit night clubs and other places where potential drug transactions takes place.

Some police officers become addicted after they finish investigating drug cases, which require them to act as undercover buyers.

To convince the dealer, they try the drugs and after the probe is over they might go too far, using the drugs for pleasure, said Adrianus.

Furthermore, some officers have used drugs before joining the force, he said.

West Java Police chief, Insp. Gen. Susno Duadji, said that in April alone, four highly ranked police officers in the province were arrested for using different kinds of drugs, including crystal methamphetamine (shabu-shabu) and ecstasy.

"It has become our commitment to clean up the police force from drugs. We conducted raids against them on purpose," he said Monday.

Last week, head of North Bogor subprecinct police Adj. Comr. Endang Rudianes, was arrested for allegedly using crystal methamphetamine with two civilian friends in his office in Pajajaran street, Bogor, West Java.

In May last year, police arrested the head of Cisarua subprecinct in Bogor, Adj. Comr Jumantoro, for keeping at his house a trader's crystal meth, ecstasy and heroine worth Rp 400 million (US$43,478). Four days later in the same town, Adj. Second Brig. Yusuf Akbar from Bogor precinct was arrested for carrying crystal meth and marijuana (ganja).

The police officers used the drugs because they did not have strong self-control, they were easily influenced by the drug environment, Susno said.(ind)