A prosecutor in suburban Philadelphia says a 3-year-old boy endured weeks of escalating abuse before he was systematically tortured over three days, ending in his death.

Chester County District Attorney Tom Hogan says what happened to the boy, Scott McMillan, was "just evilness."

The boy's mother, 31-year-old Jillian Tait, and her boyfriend, 23-year-old Gary Lee Fellenbaum, were charged Thursday with murder in the boy's death. They also were charged with aggravated assault in the beating of his older brother.

Police say the younger boy was struck with a frying pan, whipped, punched and hung upside down and beaten.

The prosecutor said late Thursday he hadn't heard the couple had obtained lawyers.

Fellenbaum's estranged wife lived with the couple in a mobile home in Coatesville, about 35 miles northwest of Philadelphia. She was charged with reckless endangerment.