"I love the street-work side of being a private investigator," said McNair, of Fishtown, who also deals with stolen-art recovery, and more brutal crimes, like rape and homicide.
"Every day is different and I never know what adventure awaits me when I answer my office phone,"she said.
McNair recently published her second nonfiction book, "Never Flirt with a Femme Fatale," focusing on a murder in 1978 and another in 1998, both in New York's Upper East Side.
McNair opens the book with her most infamous case. She was hired as a private investigator by Sante Kimes, who gained national attention when she was tried in 2000 with her son on charges that they murdered 83-year-old socialite Irene Silverman to take control of her mansion.
"My job was to help prepare Sante and [son] Kenny for the trial and track down alibis," McNair said. "I never found any alibis, and Kenny confessed to the murder of Silverman and another murder in Los Angeles so the death penalty could be taken off the table."
Both mother and son were convicted of murder and received life sentences.
"McNair has intimate firsthand knowledge a lot of crime writers don't have," said Jonathan Sipes, manager of Center City's The Next Page bookstore, which hosted a book reading and signing with McNair earlier this month. "She paints larger-than-life characters that have tragic and senseless endings."
McNair, originally from Mississippi, started her professional career as a journalist in Toronto and Rome. She then moved to New York City and flipped through the Yellow Pages to find her next career as a private investigator.
After working with firms throughout the country, McNair started Green Star Investigations in Philadelphia in 2003.
McNair agrees with colleagues who say that she has an advantage being a woman in a male-dominated field.
"Most of the male private investigators look like cops," said Anthony Spiesman, who has known her for 14 years. "McNair, on the other hand, can get blood out of a stone, and most people will open up to her."
Don't let McNair hear you calling her nonthreatening, though.
"The next person who describes me as nonthreatening," McNair said, "I'm going to bite in the leg."