

Nian Bin spent eight years on death row for murders he said he didn't commit. China's courts freed him this year after lawyers showed that police manufactured evidence. (Courtesy of the Nian family)

BEIJING – For eight years, the deaths of his neighbor’s two children have haunted Nian Bin. Police arrested Nian, tortured him into confessing to the murders and sent him to death row.

But in one of the most dramatic reversals in China’s modern legal history, Nian’s lawyers showed that police manufactured evidence against him and hid other evidence pointing to his innocence.

A high court set Nian free this fall. But the mystery endures: If Nian didn’t kill the two children, who did, and how did they die?

Read story: In China, a rare criminal case in which evidence made a difference

Hidden in the 2,000-page trove of court documents we examined for were tantalizing clues and a rare look into how Chinese police conduct such investigations and are often pressured to build cases against their chosen suspects even when evidence suggests they are not guilty.



In a police photo, Nian Bin shows investigators how he supposedly prepared poison that made victims ill. (Courtesy of lawyer Zhang Yansheng)

The case of the poisoned porridge

On the afternoon of July 27, 2006, on the fishing island of Pingtan, Nian’s neighbors sat down to eat. Sharing the dinner were Nian’s landlord, her daughter and the family of Ding Yunxia -- who ran a grocery stall next to Nian’s. They shared porridge and a dish of cooked squid. Within hours, at least four of the six people who had eaten the dinner fell violently ill. By morning, Ding’s two youngest children – ages 8 and 10 – were dead.

Police said Nian -- in revenge for losing the sale of a single pack of cigarettes the day before – had mixed rat poison into a water bottle, snuck into Ding’s apartment and poured it into a kettle later used to cook the porridge.

Two-hour gap in the tape

Nian’s confession was the cornerstone of the prosecutors’ case. The video of his interrogation by police runs four hours long. One obvious clue that coercion was involved is a sudden jump in the tape at 10 minutes and 56 seconds. Nian goes from silently refusing to answer investigators’ questions to tearfully spilling the beans.



The video interrogation of Nian Bin suddenly jumps and changes angles at 10 mins, 56 secs.

When Nian’s lawyers questioned police about it, officers first denied there was any gap. Even when they later admitted to the break, they gave contradictory explanations for it.

One of Nian’s interrogators, Weng Qifeng, told the court there was a gap because the technician had never used the camera before and accidentally turned it off. “At a little past 2 p.m., Nian Bin cried and wanted to confess,” Weng said. “We noticed the light on the camera was not on, and immediately asked the technician to turn it on.”

More than four years later, Weng recanted that version and said he didn’t remember when the camera was turned off. The technician previously blamed later said he was plenty experienced in using the camera and had simply turned it off to take a break.

A year later on March 2014, police changed their account yet again saying they had turned off the camera to prevent Nian from hurting or killing himself and turned it back on when “Nian Bin suddenly started to confess to the crime.”

The spectrometer and faked readings

By using a technique called gas chromatography-tandem mass spectrometry, the police said they found traces of poisonous fluoroacetate in the victims’ urine, heart blood, vomit, and the water in the kettle. But for years police had refused to provide the original spectrometer slides.

It’s easy to see why. When they finally released the original slides in 2013 – seven years after the original investigation -- independent experts found details suggesting police not only made mistakes in their testing but may have outright manufactured the tests to falsify the presence of poison.

Mok King-kuen, a retired Hong Kong forensic chemist, discovered that police used the same spectrum test and simply put different names on them to get a “match."

For instance, the two spectra from one of the deceased children's heart blood and vomitus were identical -- suggesting police copied from the same report for both. And the spectra from a urine sample and another labeled “standard sample” were actually snapshots of the same sample but grabbed at different times.

Furthermore, Mok and other experts say, most of the graphs if read as presented, don’t prove the existence of fluoroacetate at all.



Spectrometer reading from victim's blood



Spectrometer reading from victim's vomit

The other suspect

After years of appeals, lawyers uncovered police reports showing investigators had suspected someone else entirely of the murder.

Officers had early on focused on another neighbor who had misled police about her whereabouts, fainted under interrogation and kept rat poison in her apartment. Police had originally estimated the poison being placed sometime between 1:40 p.m. and 6 p.m. – during which period this neighbor returned to the building even though she initially told officers she hadn’t.

Police later revised the estimated time of poisoning to fit an early morning timeline that Nian provided in his confession, and they dropped the other neighbor as a suspect without explanation.



Red water bucket which hidden testimony suggests was used instead of the kettle. (Police photos publicly presented in court)

Missing witness statements

According to the police account, the victims got sick from poisoned water in a kettle used to make the porridge.

But years later, Nian’s lawyers discovered evidence that the kettle wasn’t even used to cook dinner that day. Chen Yanjiao, the landlord who cooked the porridge, told the police on the day after the incident in 2006 that she had used water from a red bucket, not the kettle.

Police, however, hid this testimony for years, together with other evidence that undermined their case against Nian.



The water kettle that Nian supposedly poured his mixture of water and rat poison into. (Police photos publicly presented in court)

The kettle

A basic principle of forensic science is that “every contact leaves a trace.” So when the police said they found the rat poison toxin fluoroacetate in water from the kettle, it seemed strange to Nian’s lawyers that investigators had only tested the water and not the kettle itself, where Nian had supposedly placed the poison.

Over the years, the kettle would become a key point of contention – used by Nian’s legal team to pick apart the police narrative.

Among the lawyers’ key questions: Why did the police wait 12 days to have the water tested? Where was the water kept, and how was it transported to the lab?

As police changed their account repeatedly of how they transported the water from the kettle to their crime lab, Nian’s lawyers grew suspicious and argued that the chain of custody for the evidence was broken, and that the sample tested could have been contaminated. Nian’s legal team used crime scene photos and experiments to disprove police’s early account of how they handled the kettle.

The enduring mystery

So how did the victims get sick? Their meal consisted of a dish of squid and the porridge. All six of them ate the porridge. But it was the four who ate substantial amounts of the squid who fell ill with stomachaches, dizziness, nausea, vomiting and spasms in the legs.

Ding’s father-in-law brought over the squid at around 1:40 p.m. Dinner began around 6 p.m. Sickness at 9 p.m. By 2 a.m. the two youngest children had died.



Nian spent eight years imprisoned for his neighbors' poisoning until being freed this fall. On death row, his hands were cuffed and shackled to his legs for years at a time. (Courtesy of the Nian family)

Recently some experts have suggested the possibility of a natural toxin in the squid. News reports suggest a wave of seafood poisoning incidents in China’s southern coastal cities in 2005 and 2006.

But this may be a hard theory to prove. Police never sent what was left of the squid dish nor the water from the red bucket used to cook the porridge for testing. Nor did they apparently send stomach content from the victims for testing. So the exact cause of the two children’s death remains unclear and the mystery left unsolved.