John Cassar, accused of murdering his mother and attempting to murder his father, told police he could not remember the alleged attacks during his police interrogation.

Inspector Kurt Colombo Zahra continued testifying in the compilation of evidence against Cassar on Monday.

Cassar, 47, stands accused of murdering his mother, Mary Grace Cassar, and attempting to murder his 74-year-old father at their Mqabba residence. He faces nine charges, including grievously injuring his father, threats and violence, heroin possession and breaching court orders. He is pleading not guilty.

Cassar was formally interrogated on 17 October at 1:11pm in the police audiovisual room by Zahra, Inspector Colin Sheldon and police officer André Mifsud. Before questioning, Cassar was again informed of his legal rights but declined legal representation, signing a declaration confirming his refusal.

Cassar repeatedly claimed that he could not remember details of the alleged killings. He told investigators that he had been under the influence of cocaine and insisted that he was "not the kind of person who would do such a thing".

Although he indicated that he had much to say, Cassar was reluctant to discuss what had happened to his parents.

Instead, he spoke about how his parents had allegedly ruined his life over the previous 14 years, before repeatedly turning the conversation towards the €7,000 he claimed had been stolen by a woman he had been dating.

Cassar told investigators that he had given mother €2,000, not €7,000.

Investigators also referred to a Facebook post published by Cassar in which he threatened to attack the woman with a chaser. When questioned about the post, Cassar told investigators: "If I wanted to find her, I knew where to find her."

Investigators also confronted him with a voice message sent to partner, warning her not to go to the family residence because his mother was dead. Cassar acknowledged sending messages to several people, including relatives, but continued to maintain that he could not recall the alleged attack.

The inspector said Cassar did not express remorse during the questioning.

Defence questions accused's mental state during negotiations

During cross-examination, defence lawyer Matthew Xuereb questioned Inspector Kurt Colombo Zahra extensively about Cassar's behaviour during the crisis negotiations preceding his arrest.

Zahra confirmed that Cassar had been highly agitated, was not behaving rationally and frequently shifted between unrelated subjects, making it difficult to maintain a coherent conversation.

The defence also questioned whether Cassar appeared emotionally distressed. Zahra replied that he had detected more anger than hurt in his behaviour.

Zahra confirmed that during the negotiations, Cassar had voluntarily declared that he had killed both his mother and father. However, the inspector insisted that his role at that stage was to stabilise the situation and secure a peaceful surrender, rather than conduct an interrogation. He maintained that he had deliberately refrained from asking potentially incriminating questions and that Cassar's statements about the alleged killings had been made voluntarily.

Zahra also established that approximately three video calls had taken place between the police and Cassar on the night of his arrest. He confirmed that the calls had not been formally recorded and said he did not know whether police body cameras had captured them.

Defence raises doubts on accused's mental state during interrogation

Xuereb also questioned whether Cassar had been medically fit to undergo interrogation following his hospitalisation. The defence referred to a psychiatric certificate describing Cassar as being in a stable mental state, not agitated and free from psychotic symptoms.

However, the certificate expressly stated that it was not a fitness-to-plead certificate.

Zahra explained that the certificate did not determine whether Cassar was fit to plead, an issue which could become relevant if an insanity plea were raised.

A separate certificate issued by Anthony Falzon stated also that Cassar was fit to remain in police custody.

The inspector said he had relied on the two medical assessments in concluding that Cassar could be interrogated.

Xuereb questioned whether investigators had established what medication or treatment Cassar had received while hospitalised. Zahra acknowledged that he did not know exactly what medication had been administered.

Asked whether Cassar could have been sedated or in a state of shock, Zahra said he could not rule out sedation but did not personally believe the accused had been in shock. He maintained that medical doctors would be better placed to determine his condition.

The defence also questioned Zahra about items recovered during a search at Cassar's residence. Asked whether police had found medication, Zahra said they found foil and other items associated with drug use.

Zahra confirmed that Cassar eventually emerged voluntarily from the property where he had barricaded himself, raising his hands and lowering his shorts to demonstrate that he was not carrying a weapon.

Although he cooperated with his arrest, the inspector said Cassar remained agitated and repeatedly requested a cigarette. Zahra placed a cigarette in his mouth, which another officer lit for him.

The inspector explained that Cassar was subsequently taken to Mater Dei Hospital after emergency doctors expressed concern about the possibility of a heart attack.

Police had been searching for Cassar before alleged killings

During cross-examination, Xuereb questioned Zahra about a domestic violence report filed by Cassar's estranged wife, Rosalie Cassar, on 14 October. Zahra confirmed that police had been actively searching for Cassar and had attempted to locate him on the morning of 15 October.

However, Attorney General lawyer Kaylie Bonett objected to the line of questioning, arguing that the proceedings concerned the homicide rather than the separate domestic violence report. Zahra clarified that he was not responsible for that investigation. Asked whether Cassar had been aware of the domestic violence report before the alleged killings, Zahra confirmed that the accused had learned of it when he contacted Rosalie using his mother's mobile phone.

The prosecution is being led by Inspectors Colin Sheldon and Kurt Colombo Zahra, assisted by Attorney General lawyer Kaylie Bonett.

Defence lawyer Matthew Xuereb is representing Cassar.

Magistrate Ingrid Bianco is presiding over the case.