Investigators in Philadelphia are following leads in the killing of a pediatrician found hogtied and on fire in the basement of her home, and an arrest could be made as early as Friday morning, ABC News sources said.
Police also reportedly had taken a person of interest into custody in the case, ABC News station WPVI in Philadelphia reported, though initially few details were available.
The developments came after investigators collected hours of surveillance video and canvassed the neighborhood where police on Monday found the body of Melissa Ketunuti, 35, a beloved doctor at Children's Hospital of Philadelphia.
Ketunuti's body was found Monday in the basement of her Graduate Hospital-area row house after her dog walker called 911. Her wrists and ankles were bound behind her back, and she was on fire, police said.
The pediatrician was fully clothed and there were no signs of sexual assault, sources said.
Investigators said she had been strangled with a rope around her neck. However they are awaiting the results of an autopsy to determine the cause of death.
With no evidence of forced entry, police wondered whether she knew whoever attacked her.
"We don't know if she walked in on individuals inside of her property," Philadelphia police Capt. James Clark said. "We don't know if it's a known doer or an unknown doer."
There was no clear motive, and nothing appeared to have been stolen. Police have questioned Ketunuti's boyfriend, but he has not been declared a suspect.
"We haven't ruled out anyone," Clark said today.
The reward for information leading to the arrest and conviction of the person responsible for Ketunuti's death has swelled to $35,000 after community groups contributed money. The total reward includes the $20,000 offered by the city of Philadelphia.
Police have been looking at surveillance tapes from the area hoping to spot the killer and have questioned area residents about what they saw that day.
The culprit will likely be close to home and someone Ketunuti knew, said ABC News consultant and former FBI agent Brad Garrett.
"This is extremely personal. I can't think of anything more heinous or cold to do to another human being," he said. "The boyfriend can provide all kinds of leads: who she knows, what problems she was having at work."
Ketunuti lived alone on a quiet street and had been there for about three years.
"[She was] super pleasant, really nice," one neighbor said. "Just super friendly."
Ketunuti's hospital issued a statement Tuesday that she was "a warm, caring, earnest, bright young woman with her whole future ahead of her," adding that she will be deeply missed.
"It's going to be just a horrible thing for her family," a neighbor said. "She was just a very nice person, very full of life."