Lim Chin Huat said his client Kang Chang Heng, 38, had complained of voices in his head.
Magistrate Mohd Isa Md Nor then stood down the hearing to consider the request.
Lim told Mohd Isa that Kang suffered from serious hallucinations and that he seemed to hear voices inside his head telling him to do certain things.
In a report by The Star, Lim said according to Kang’s family, he had also tried to jump from his fourth-floor flat.
“The defence requests under Section 342(3) of the Criminal Procedure Code for an order to allow my client to be sent for psychiatric observation for a month,” he was quoted as saying.
According to the report, Kang signalled earlier today that he understood the charges against him after a sign language interpreter conveyed the content of the charges which were read by a court interpreter.
The sign language interpreter was brought in today after the case was postponed on Dec 19 as Kang, a furniture factory worker from Kepong, failed to respond when the charge was read out to him.
Kang has been charged with murdering Chia Tee Nang, 73, his 68-year-old wife Lim Mai Shak and the couple’s grandsons Ryan Chia Zeng Xi, 10, and Chia Yuan Bin, three, at a house on Jalan Tepi Laut, Tanjung Sepat, Selangor, between 4am and 5am on Dec 13.
He faces the mandatory death sentence if found guilty.
Kang also faces a charge of voluntarily causing hurt to 12-year-old Andrew Chia Zeng Haol at the same date, time and place.