Police are still tracking down witnesses related to the 1MDB investigation, inspector-general of police Khalid Abu Bakar said.

"We are still required to carry out further inquiries, so that's what we're doing now.

"Some witnesses are available, some are not. We need time to detect these witnesses," Khalid said at a press conference in Kuala Lumpur today.

He declined to name these individuals.

Khalid said the police had previously submitted their investigation papers to the Attorney-General's Chambers, but it was returned and therefore the investigation must continue.

In April, Khalid announced the formation of a special team to probe 1MDB for possible criminal breach of trust.

This came after recommendations were made by the parliamentary Public Accounts Committee.

The police had completed the first phase of their investigation into the troubled state fund in August and are currently still in the second phase of the probe.

The opposition had criticised the police for dragging their feet over this investigation.

On a separate matter, the IGP today also commented on the incident of a doctor who was allegedly assaulted by an elite federal police team after he was mistaken for a robber.

He explained that the police team raided a row of food stalls in Serdang on Oct 7 in search of a few suspects who had been breaking into houses in the area.

The police knew the suspects were going to be there and had told everyone else in that area to stay put when the raid happened, he said.

However, when the raid started, the doctor, along with the suspects, tried to flee the scene.

"The doctor also ran, I mean he ran helter-skelter, so the police thought he was one of the suspects.

"That was what actually happened. I think if you've got nothing to do with any police case, when the police tell you to stay put, you should stay put," he said.

Though he regretted the incident, Khalid said the police will not apologise for what happened as they were only carrying out their duties.

However, according to TheSun, the doctor had tried to flee because he believed the police were robbers.

The doctor wrote in his police report that the men had no identification or police logo on their gear, the daily reported.