JAKARTA: Indonesia's police are conducting preliminary inquiries into whether any actions by officials at the country's drug regulator could amount to criminal wrongdoing, as they expand a probe into tainted cough syrups linked to the deaths of more than 200 children across the nation, two top inspectors told Reuters.

The police scrutiny of Indonesia's food and drugs agency (BPOM) is the latest escalation by states seeking accountability for contaminated syrups that were linked to the deaths of dozens more children in Gambia and Uzbekistan last year. The World Health Organization is working with countries to investigate the global pharmaceutical supply chain for such syrups.

Late last year police arrested and charged eight individuals at Indonesian companies that imported and distributed raw materials to drugmakers whose cough syrups were found to contain toxic industrial-grade chemicals instead of the legitimate ingredient.

Andika Urrasyidin, lead police investigator of the case, told Reuters police have called in "many" BPOM officials for questioning, and the investigation is still underway.

"We're still looking into it. But ... if there were actions, then yes there needs to be responsibility," he said, declining to say what, if any, charges may be brought.

No one at BPOM has been accused of wrongdoing. The police could ultimately pursue criminal charges or close the probe without taking action.

Officials from the BPOM did not respond to a request for comment.

Hersadwi Rusdiyono, the director of Indonesia's national police's crimes detection unit, said BPOM officials were brought in as witnesses, but investigators are now checking if any wrongdoing was committed by drug regulators.

"We asked them according to their functions, as regulators, whether they've conducted supervision and what kind of supervision," he told Reuters. "They were only interrogated as witnesses, we're coordinating with the prosecutors."

Hersadwi said the probe so far has focused on staff at lower levels and not included BPOM'S chief, Penny Lukito. Penny did not respond to a request for comment.

BPOM has said a spike in cases of acute kidney injury occurred as several parties "exploited a gap in the safety guarantee system" and pharmaceutical companies did not sufficiently check the raw ingredients they used.

In January, Pipit Rismanto, a senior police official, told reporters the authorities had found one company sold "industrial-grade" toxins as pharmaceutical-grade propylene glycol, a key base of syrupy medicines.

The toxins, ethylene glycol (EG) and diethyelene glycol (DEG), can be used by unscrupulous actors as a substitute for propylene glycol because they can cost less than half the price, several pharmaceutical experts told Reuters.

Police have charged four companies involved in the case -- drugmaker Afi Farma, which allegedly sold tainted syrups, CV Samudera Chemical, which according to the police supplied the chemicals, and two of its distributors Tirta Buana Kemindo and Anugrah Perdana Gemilang.

A lawyer for Afi Farma, which attended its first court hearing on the case on Tuesday, said the company would respect the law.

Tirta Buana Kemindo declined to comment. CV Samudera and Anugerah Perdana Gemilang could not be reached.

BPOM is also named in a separate class action suit launched in January by parents whose children died or are suffering from long-term complications of the acute kidney injury.

The first day of trial has not been scheduled and a mediation process has just concluded, said the families' lawyer.