Psychologist Explains Rationality Theory in Madiun Murder Case
Forensic psychologist Reza Indragiri Amriel has discussed the theory of rationality, or awareness, in relation to the alleged premeditated murder of Dini Hardiyanti, 30, the suspect’s unregistered wife, and her four-year-old child, AGF, in Madiun, East Java. The suspect is Dwi Bagus Martono, also known as Bagus or DBM, 40.
“Removing witnesses and destroying evidence—which in this case means the victims’ bodies—and that is what the perpetrator has done, indicates rationality,” Reza told CNN Indonesia on Tuesday (27 October).
Police arrested Bagus over the alleged premeditated murders of his unregistered wife and young child. He is suspected of killing them brutally, then burning and crushing their remains with a grinding machine.
Reza said the issue of mutilation should initially be set aside, because the central criminal act was the suspected perpetrator’s taking of the victims’ lives.
He first highlighted discrepancies between police statements and reports circulating in the media. These concerned the nature of the incident—whether it was a premeditated crime or the result of a momentary emotional outburst.
“Although the difference may seem slight, these are in fact different psychological processes, which also have implications for which legal provision is applied,” he said.
Reza explained that four elements must all be present before an act is committed to establish premeditation: a target, an incentive, resources and risk. He urged investigators to examine each element thoroughly in order to ensure the perpetrator is held to the fullest extent of the law.
“Police can investigate as carefully as possible and use the most precise wording or explanations to ensure that what is described as a premeditated crime is genuinely proven,” he said.
Reza added that burning and grinding human remains are typical methods used by offenders who are mentally well, rational and sane to destroy evidence or eliminate witnesses. Nevertheless, he said the focus should not be on the brutality of these acts, but on whether the crime was planned or spontaneous.
“We should use only one assumption: that the perpetrator is healthy, has no mental disorder, is sane, normal and rational—even if, in fact, this was a planned act,” he said.
The Journal of Human and Education (JAHE) describes Rational Choice Theory (RCT) in criminology as viewing crime as the result of a decision-making process in which an offender considers the conditions and options available. The theory regards offenders as individuals with particular goals who weigh the benefits, costs, opportunities and risks of a criminal act.
In the Indonesian context, RCT is used to explain that offenders are influenced not only by motive, but also by the consequences and circumstances surrounding their decision to commit a crime.
According to police, psychological examinations indicate that Bagus has an above-average IQ. He graduated from a prominent polytechnic in Bandung and currently works as an offshore oil-drilling specialist.
Bagus faces the death penalty, as authorities have charged him with premeditated murder.
Premeditated murder is regulated under Article 459 of Law No. 1 of 2023 on the Criminal Code. The article states that anyone who deliberately takes another person’s life after prior planning is guilty of premeditated murder and may be sentenced to death, life imprisonment or a maximum of 20 years in prison.