The march took place after an exterminator was formally charged with Dr. Melissa Ketunuti's murder and with abuse of a corpse.
Dozens of people gathered on the quiet block south of Rittenhouse Square for the vigil, KYW-TV reported. Ketunuti's dog walker found her body, tied up and burning, in the basement of the house early Monday afternoon.
Jason Smith, 36, was arraigned by videolink from jail. Smith was arrested Wednesday at his home in suburban Levittown, Pa.
Neighbors say Smith lived with his girlfriend, their young daughter and members of her family and was often seen walking his dog, The Philadelphia Inquirer reported. They described him as friendly.
Smith, who spent a month in jail several years ago after he admitted driving under the influence of drugs and alcohol, told investigators he was still abusing both, police said at a news conference. He allegedly admitted killing Ketunuti, saying he "snapped" when they got into an argument while he was working at her house, hit her and then tied her up and strangled her, setting the body on fire in an effort to destroy evidence.
Ketunuti worked at Children's Hospital of Philadelphia, one of the country's top pediatric facilities.