Marybeth Tinning

Marybeth Roe Tinning (born September 11, 1942) is an American murderer and suspected serial killer who was convicted in New York State of the murder of her ninth child, 4-month-old daughter Tami Lynne, on December 20, 1985. She is suspected to be similarly involved in the previous deaths of her eight children, all of which took place within the span of fourteen years.

The causes of death for Tinning's first eight children was initially thought to be genetic. Even when their sixth child, Michael – who was adopted and not of blood relation – died in 1981, authorities failed to open an investigation. Eventually, Schenectady County prosecutors had enough evidence – a laboratory test indicating death from asphyxia by suffocation – to charge Tinning in Tami Lynne's death. In July 1987, she was convicted of second-degree murder and sentenced to twenty years to life in prison. An appeal to the New York Supreme Court, arguing that her confession was coerced and there was insufficient evidence to convict her, was denied.

It is unclear if Tinning has ever been diagnosed with Munchausen syndrome by proxy (MSbP). Some believe that her pattern of behavior aligns perfectly with the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition's (DSM-5) Development and Course section on the disorder: "In individuals with recurrent episodes of falsification of signs and symptoms of illness and/or induction of injury, this pattern of successive deceptive contact with medical personnel, including hospitalizations, may become lifelong."

Tinning was incarcerated at Taconic Correctional Facility in Bedford Hills, New York. She was denied parole six times, but was granted parole at her seventh hearing in July 2018 and was released on August 21 of that year.