The police have detained a 16-year-old schoolboy to facilitate investigations into the murder of three sisters in Alor Semela, off Jalan Datuk Kumbar here on Friday.
The suspect, an acquaintance of one of the victims, Nor Syafikah Nadia Rusdi, 14, was picked up at his family home in Perlis about 11.30pm, Sunday.
Kota Setar police chief ACP Adzaman Mohd Jan told reporters at his office here, the schoolboy was remanded for four days, beginning Monday, to shed light on the killings.
He said the police had classified the case as murder.
The semi-nude body of Nor Syafikah Nadia was found at a padi field in Alor Senibong, Langgar at 3.45pm on Saturday.
The bodies of her sisters, Puteri Nurul Akma, three, and Nur Izzati Husna, 12, were found at a canal in Kampung Padang Tani about 4pm yesterday, about 3.5km away.
On Friday, the three sisters left home on a motorcycle for a friend's house in Kampung Gelam at 7.30pm.
Adzaman said the police were in the midst of determining the relationship between the student and the victims in all aspects, and had interviewed more than 10 people, including family members and friends of the deceased to assist in the investigations.
He said a post-mortem on Puteri Nurul Akma and Nur Izzati Husna concluded the cause of death as drowning.
"Nevertheless, there was no sign of scratches on the bodies, and they were not raped, strangled or beaten up.
"The three sisters died at almost the same time," he said, adding that blood samples from the trio were sent for analyses by the Chemistry Department in Penang to ascertain whether death was due to drug injection or other causes.
Adzaman urged the public to stop speculating that the victims were raped as highlighted in some social websites.
"Forensic experts have confirmed that there was no sign of the sisters having been raped," he said.