Now, three weeks later, he's safe at home.
"Call it a miracle, call it a blessing, somehow Marley showed up at 3 a.m. in the morning," she said.
It's been a long journey home for Marley. He was at the vet's office to get fixed. But after the surgery, he suffered complications and had to have surgery to fix a bleeding problem.
She later heard from the vet's office was that Marley had escaped by jumping over an 8 foot fence.
"When I went to go talk to the vet and find out what's going on, he refused to talk to me," said Nicholas.
Nicholas lives less than a half a mile from the vet's office. She hung posters and looked tirelessly for Marley, but says she couldn't understand how he was able to escape.
"How could he run away after having a surgery like that? He could barely move," said Nicholas.
She turned to ABC11 Eyewitness News I-Team Troubleshooter Diane Wilson, and we aired her story. The next day, she got a letter from the vet assuring her he did not harm Marley, and that Marley did escape by jumping the fence.
The letter said it was the first dog ever to escape in his 40 years of practice. He stated in the letter he took full responsibility and even offered to make up some posters and include a $100 reward for giving Marley back.
But it turned out that was not needed, because early Monday morning Nicholas says she heard a horn honk outside her home, opened the door, and then got a big surprise.
"It looked like he was just smiling at me, and I took a double take and made sure I wasn't dreaming," she said. "If someone did anonymously bring him home, I want to say thank you."
While Nicholas is grateful to have her Marley home, she's still angry he even escaped from the vet's office in the first place. She's filed a small claims case and says she's filing a complaint with the state's veterinary board.
We tried to reach out to the vet, but a member of his staff said they have no comment.