The stench inside a room where an intellectually disabled woman was locked for 17 hours a day with two dogs was described in court as "unbearable" by a police sergeant today.

Officer Lydon Zammit said he was left with a lasting memory of the strong smell of dog urine and faeces inside the room where the 39-year-old woman was locked.

The squalid room also had a bucket which the woman used as a toilet, and mounds of clothes were scattered across the room.

The police raided the Birzebbuga apartment after they were informed about the case by a woman who used to live in the same apartment.

The sergeant was testifying in the compilation of evidence against Anna Maria Jimenez, a 33-year-old Maltese woman, who is pleading not guilty to locking up the victim, threatening her, assaulting her and causing her slight injuries.

Ms Jimenez is also charged with threatening a 29-year-old woman who has been her flatmate for the past five months.

Mr Zammit told Magistrate Claire Stafrace Zammit that the police began investigating the case after the 29-year-old left the apartment and informed police about the horrors inside.

Ms Jimenez would lock up the victim in her “bedroom” and would give her Playmobil parts for her to put together, which she would then exchange for money at the factory, the court heard.

Ms Jimenez, who works as a cleaner at Mater Dei Hospital, would unlock her upon her return from work at around 3pm when she would feed her and clean the room.

"When we went to the apartment, the smell was overpowering and sickening. The smell was so unbearable that it was difficult for us to spend much time in there," the sergeant testified

He said that after the police intervened, the 39-year-old victim thanked the police for saving her from her nine-year ordeal.

The 29-year-old flatmate told the magistrate how she felt threatened by Ms Jimenez, who had helped her find a job as a cleaner at the same hospital.

She testified about how she was asked to pay more money for rent and had also been pressured to give Ms Jimenez her bank card and the PIN number.

The woman said she had occasionally seen Ms Jimenez slapping the 39-year-old victim.

The case continues on Friday when the 39-year-old victim is expected to testify via video conferencing.

Police Inspectors Joseph Busuttil and Sylvana Briffa are prosecuting and lawyers Joe Giglio and Mario Spiteri are appearing for the accused.