PHILADELPHIA (AP) — The reward for information in the killing of a pediatrician found bound and burned inside her downtown home has grown to $35,000, officials said Wednesday.

Firefighters responding to the home on Monday afternoon found Melissa Ketunuti's body on fire in the basement, with her ankles and wrists bound.

Ketunuti, a second-year infectious-diseases fellow and researcher at Children's Hospital of Philadelphia, had been strangled, police said.

Homicide Capt. James Clark and other officials said Wednesday that the Citizen's Crime Commission will administer $15,000 offered by private donors, which will be added to the $20,000 offered by police for an arrest and conviction in the homicide.

Police said they don't know whether Ketunuti, 35, knew her killer but there were no signs of forced entry into her home.

"We don't know if she walked in on individuals inside her property," Clark said. "We don't know if individuals forced her inside of her property."

Clark said investigators have been following up on tips and viewing surveillance video from security cameras near Ketunuti's home. He said he was confident that police eventually would be able to make an arrest in the case.