She had found a box in her car, which she was standing next to, and was attempting to get the kitten inside her vehicle when another car pulled up on the other side of hers.
"A guy and a girl came out and I think there were at least two people in the back. The first two went inside and got some food, then came out and started talking to me.
"It was kind of weird because the guy kept stomping his foot down, to scare the kitten. I kept saying to him: 'Dude, can you not do that'?"
It was only later when she realised what the pair had been doing - distracting her as the others in the vehicle next to hers stole her bag and phone.
"I just felt sick when I figured it out. I just couldn't believe it."
What made it doubly painful was that inside Ms McMullan's bag - which also held a Kindle, wallet, money and medication - was her phone, on which she had saved voice messages from her father, who died of cancer a few years ago.
"When my dad was diagnosed, he only had six weeks to live ... so some of the messages towards the end of his life were ones I would listen to," Ms McMullan said tearfully.
Ms McMullan, a publicist, has filed a complaint with police and is now offering a reward for the return of her cellphone.