(AFP)--Dubbed the "Black Widow" after the mate-eating spider, Chisako Kakehi awaits trial: Initially arrested on suspicion of murdering eight lovers for insurance payouts, her case is notorious in Japan as much for its body count as the shortcomings of the investigation.
No autopsies were reportedly performed on six of those eight at the time of death, a situation experts say is indicative of Japan's flawed system, warning the country's low post mortem exam rate may mean criminals are getting away with murder.
In 2014, 11.7% of "unusual deaths" -- the term used for cases in which cause is not immediately clear -- resulted in autopsies, National Police Agency (NPA) figures show. That compares with 40% in England and Wales in 2014. And in Sweden, autopsies are performed on 95% of "unclear" deaths, according to the National Board of Forensic Medicine.
"The low autopsy rate means there is a higher chance crimes are being overlooked," said Hirotaro Iwase, professor at the forensic medicine department of Chiba University.
Despite government pledges to increase the autopsy rate to 20% by this year, the figure remains around half that. Iwase attributes this to a shortage of forensic specialists as well as budget cuts at public universities, which carry out the majority of the crime-related procedure.
Some university forensic departments are on the verge of collapse -- 20 out of Japan's 47 provinces have only one professor performing autopsies, according to the Japanese Society of Forensic Medicine.
In the Kakehi case, police initially determined her previous partners died from illness. Her arrest only came after police discovered her most recent husband, 75-year-old Isao Kakehi, died from cyanide poisoning and began looking into the earlier cases and found a pattern.
The 69-year-old has been charged with three murders and one attempted murder. Police investigated four other cases but ultimately could not find sufficient evidence to charge her, according to local media reports.
"Crime is being overlooked"
According to OECD data on safety published in 2015, the homicide rate, which is the number of murders per 100,000 people, was only 0.3 in Japan while it was 5.2 in the US, 0.6 in France and 0.5 in Germany.
There were 933 murder and attempted murder cases in 2015 in Japan, according to police, with the number on a declining trend since 2004, but the low autopsy rate may be hiding the true figure, experts say.
"I believe crimes would be less overlooked if there is a system where autopsies are conducted on bodies where the cause of death is unclear even if the cases are not suspicious," explained Professor Shinichi Kubo, a forensic scientist at Fukuoka University.
Hidemichi Morosawa, an expert on police investigation at Tokiwa University, said he suspects part of the problem is that officers likely prefer to avoid the demands of murder cases, a huge burden on workloads.
"Police should send as many bodies as possible for autopsies" to increase the chance of determining possible foul play, he told AFP.
But due to the shortage of qualified forensics staff, police with more than one corpse needing urgent examination often have to drive hours to neighbouring provinces for autopsies to be performed.
It took three deaths for police to arrest Kanae Kijima in 2010, who allegedly killed her boyfriends through carbon monoxide poisoning -- she burned charcoal inside after giving the men sleeping pills to knock them out.
Police initially determined the first victim had committed suicide therefore did not conduct a postmortem examination. Kijima was found guilty and sentenced to death.
And in 2007, when teenage sumo wrestler Takashi Saito died during training, police concluded he had succumbed to heart failure. His parents, suspicious of the circumstances around his passing, demanded an autopsy, which determined he was beaten to death.
Performing autopsies is arduous and can take up to two days if a body is badly damaged, Iwase said, adding that specialists face a high risk of contracting Hepatitis C or HIV.
And despite such challenges, forensic scientists on university salaries often earn less than doctors working at even small hospitals and also must juggle autopsies with academic research and teaching.
Police have been beefing up the number of officers qualified to conduct visual postmortem inspections, jumping to 340 last year from 160 in 2008, according to the NPA.
They must have more than 10 years of experience in murder cases as well as 10 weeks of special training, said Kazuhito Shinka, who heads the NPA division supervising post mortem inspections.
"It's important for police to cooperate with doctors with forensic knowledge," he told AFP.
But Shinka added thorough investigations of relatives of the dead are needed to ascertain any motives for murder.
Iwase says authorities have "lost their motivation" to improve the situation.
"Ministries are running away from their responsibilities and they're avoiding budget requests. As a result, the autopsy rate does not improve," he said.
In a sign lessons are being learned from the Kakehi case, from April, police will conduct toxicology tests on all bodies that they handle.
Iwase added toxicology tests were also necessary to help determine the cause of death.
He explained: "You cannot detect crimes just by conducting an autopsy. You need to fully carry out a toxicology test as well. Otherwise you'll miss crimes."