KUALA LUMPUR, Malaysia - Prosecutors in the Malaysian trial of two women accused of killing the estranged half brother of North Korea's leader could finish their case in the second quarter of next year, defence lawyers said Thursday as another week of testimony concluded.

The only two suspects in custody, Indonesian Siti Aisyah and Doan Thi Huong of Vietnam, pleaded not guilty at the start of their trial Oct. 2, but prosecutors have said four North Koreans conspired with the two women to plot the murder of Kim Jong Nam and fled the country the day of the attack.

The hearing has been postponed several times this month after police investigating officer Wan Azirul Nizam Che Wan Aziz forgot to bring his investigation notes and defence lawyers had to wait for him to supply documents. Defence lawyers have described Wan Azirul as the most important witness.

Gooi Soon Seng, Aisyah's lawyer, this week told the court that he can only resume his cross-examination of Wan Azirul after studying the latest documents supplied by the police officer: more than 70,000 pages of content in the Korean language found in mobile phones belonging to North Korean chemist Ri Jong Chol.

Ri was detained shortly after the murder but released due to lack of evidence and deported.

Gooi said Ri, who used a North Korean embassy car since 2015, was a key suspect as his house could have been a clandestine lab to make VX nerve agent.

"This case hinges on circumstantial evidence. Apart from the (airport video) footages, there is no direct witness in the case. We want to show that the police officer is lopsided in his investigations, that he didn't bother to probe the motive in the murder," Gooi told The Associated Press.

"Four men have escaped and they are putting the blame on the girls to make it look like a simple murder. But if you put all the circumstances together, it's a political murder in which the girls have no interest in. We have to show how they are used as scapegoats and they don't know what they are doing," he said.

The trial will resume Nov. 28 for four days and then continue over several dates in January, February and March. The schedule takes into account public holidays and the other duties of the lawyers involved.

So far, 18 witnesses have testified and prosecutors said they have about 20 more minor witnesses.

"The reason for the delay is because a lot of the documents were not supplied to defence from the start, but hopefully it ends in March," said Salim Bashir, one of Huong's lawyers. After both prosecution and defence make their submissions based on evidence adduced in court, the judge is likely to take a month or more for a ruling, possibly by the second quarter of 2018, he said.

It will be the end if the judge finds there is no case against the women and they are freed. But if defence is called, the trial could then take another few months. The women face the death sentence if found guilty.

This story has been corrected to show the timing refers to when the prosecution's case is expected to end, and the judge could call the defence rather than issuing a verdict at that time.