most evil
murderous women (3/6)

This documentary series delves inside the mind of killers in an attempt to find out why they kill; how they get away with their crimes and how they rationalise their actions. In each programme, Dr Michael Stone, a forensic psychiatrist at New York City’s Columbia University, considers killers and places them on his ‘most evil’ scale, which he has devised to categorise murderers. In tonight’s edition, Dr Stone assesses a relatively rare type of murderer: the female killer. With 93 per cent of murders in the USA committed by men, what drives the few female killers to homicidal acts?

Most women who kill are placed on the lower levels of Dr Stone’s scale of evil, which is reserved for crimes of passion and other impulsive acts. Those who climb higher, Dr Stone has discovered, follow similar patterns to each other – the majority killing people in their intimate circle, such as their spouses, sexual partners, children or parents.

Marybeth Tinning was one of these killers. Living in Schenectady, New York, with husband Joe and young children Barbara and Joseph Junior, Marybeth was devastated when her father suddenly died. A few months later, the family was hit by another tragedy when their new baby, Jennifer, died after being diagnosed with meningitis. Nearly three weeks after this, Marybeth brought two-year-old Joseph Junior to the hospital, claiming that he had suffered a seizure – but doctors sent them home. Marybeth brought Joseph back to the hospital just a few hours later, and he was pronounced dead, cause unknown.

When the same thing happened with four-yearold Barbara, it meant that all three of Marybeth’s children had died inside 90 days. Over the following years, each of her subsequent children died, prompting concerns that a genetic disorder could be to blame for the tragedies. However, when an adopted child also died, the concern gave way to suspicion. It was only when three-month-old Tammy-Lynn died in 1985, that police brought in Marybeth Tinning for questioning. She confessed to smothering three of the nine children to die in her care, but denied harming the six others.

Dr Stone believes that Marybeth’s past, in which she was denied attention by a cold father and had few friends, could be a factor in her later behaviour. “It may have been a tragic attempt to get the attention she always craved,” he suggests, placing her at seven on his scale: a highly egocentric killer who murders loved ones for narcissistic reasons.

Although many female killers target those close to them, Cathy Wood and Gwendolyn Graham preyed on strangers. Working together as nurses’ aides in a Michigan nursing home, the pair developed a deep bond which turned into a sexual relationship. They enjoyed playing practical jokes on patients and fellow staff, and eventually hatched a sadistic plot to kill some of the home’s elderly residents – spelling out ‘Murder’ with their victims’ initials. Dr Stone puts the pair at number 16 on his scale, as they killed for joy and to solidify their bond.

The highest levels of Dr Stone’s scale are reserved for sadistic murderers, who inflict prolonged torture on their victims. Few women are in these ranks, says Dr Stone, as females are less likely to be sadistic. Rare examples however include Theresa Knorr, who tortured her six children, murdering two of them, and Jessica Schwartz, who was found guilty of the prolonged abuse and second-degree murder of her stepson AJ.

The programme also examines the case of Susan Smith, who claimed her two sons had been abducted before confessing to their murders; and serial killer Aileen Wuornos, whose story was dramatised in the 2003 film ‘Monster’.