Updated

The parents of a young Philadelphia doctor allegedly killed in her home by an exterminator said Friday their daughter was a "dedicated physician" whose death has left "an enormous gap" in their lives.

An emailed statement from a spokeswoman for Dr. Melissa Ketunuti's parents said the Children's Hospital of Philadelphia researcher's loved ones "are devastated by this senseless act of violence that has ended the life of someone who was so loved, cherished and admired."

"Melissa was a source of joy to everyone in her life," said the statement released Friday.

The family spokeswoman, Manisha Pai, who once Ketunuti's college roommate, said the parents don't want to be mentioned by name and are asking for privacy. They arrived in Philadelphia from their home in Thailand on Friday.

A man hired to deal with a mouse problem in Ketunuti's downtown row home is charged with strangling her with a rope after they got into an argument in her basement, then tying her up and setting her body on fire.

Jason Smith, 36, of suburban Levittown admitted to the crime, according to police. He is being held without bail on charges of murder, arson, abuse of a corpse and risking a catastrophe.

"Melissa's friends from childhood, college, residency and elsewhere remember her many kindnesses, even during long hours, as well as her zest for life: traveling, running and spending time with friends and family," the parents' statement said.

They called her "a loving daughter and friend, a dedicated physician and a talented researcher" with a passion for medicine that inspired those who worked with her.

Investigators said Smith, who lived with his longtime girlfriend and her young child, and Ketunuti, a second-year infectious-diseases fellow and researcher, had never met before. Police would not elaborate on the substance of the fatal argument.

Dr. Paul Offit, chief of the hospital's division of infectious diseases where Ketunuti worked, said she was interested in finding ways to prevent life-threatening childhood infections in the developing world -- particularly Botswana, where the rates of AIDS and HIV are among the highest in the world.

He described Ketunuti as a "soft-spoken, gentle, kind, straightforward person -- irony wasn't in her repertoire."

Offit recalled the young doctor telling him that she had initially wanted to pursue a career as a surgeon but changed to pediatrics after realizing that she could have a greater positive impact in the world.

"She dedicated her life to trying to make children's lives better," he said. "She wanted to make a difference. She would have."