THOUSAND OAKS : Brain Damage Cited at Thornton Hearing

Convicted Thousand Oaks killer Mark Scott Thornton suffered a “precipitous” slowdown in weight gain during the first six months of his life, a defense expert testified Thursday, saying it possibly led to brain damage.

Ventura pediatrician Robert Fostakowsky said medical records show that Thornton weighed eight pounds, five ounces at birth but had grown to only 13 pounds, 14 ounces six months later.

A Superior Court jury is deciding whether Thornton should die for the September, 1993, killing of Westlake nurse Kellie O’Sullivan.

The panel, which convicted Thornton of first-degree murder in December, also has the option of sentencing him to life in prison without the possibility of parole.

Testifying at Thornton’s death-penalty hearing, Fostakowsky said the falloff in weight gain suggests that the defendant suffered from a developmental disorder known as Failure to Thrive, a disorder that essentially means his growth was stunted.

Defense attorneys attributed the lack of growth to neglect. Thornton’s mother has testified that she was a 19-year-old drug user and high school dropout who suffered postpartum depression after her son’s birth in July, 1974.

Under cross-examination, Fostakowsky acknowledged that Thornton has grown to become an average-sized adult, weighing 150 pounds and 5 feet, 8 inches tall. The pediatrician further conceded that the weight falloff could have been due to Thornton’s childhood development.

In other testimony, an obstetrician who delivered Thornton said the birth was complicated and could have resulted in brain damage. Thornton was given his middle name after that physician, Dr. Lawrence W. Scott.