BOSTON (CBS) – A 19-year-old and her family are expressing their gratitude toward a Boston Police Department captain after his “amazing and generous act of kindness.”

Kori Malenfant took to Facebook over the weekend to share her journey home to Maine from New York, where she underwent brain surgery days earlier at Presbyterian Hospital.

Weather-related delays caused Malenfant and her parents to be stuck at a “very cold” North Station Saturday, with the next train to Portland not scheduled for another 2-and-a-half hours.

She writes her parents were “feeling desperate” because of her surgery, as there was no comfortable seating or support for her neck available. Malenfant told The Boston Globe she had an operation on January 2 to correct a Chiari malformation, in which brain tissue extends into the spinal cord, causing pain.

Her parents spoke with two Boston police officers on duty asking if there was a place to store their luggage while they waited somewhere warmer, and the officers said they’d contact their supervisor.

That’s when Boston Police Capt. Kelley McCormick showed up and asked the family to follow him to his unmarked police SUV. Malenfant said he told them “we were going to go for a little ride.”

The family assumed that meant he would drive them around a bit to stay warm, but it soon became apparent they were heading north.

“Mom asked where we were going, and he laughed and said he was kidnapping us and that it was perfectly legal,” Malenfant said. “We soon realized he was driving us all the way to Portland, back to our car!”

Malenfant said McCormick told them there was no way he was going to let her sit in the cold after undergoing surgery.

“We were all in shock and very emotional at this amazing and generous act of kindness,” she said.

During the ride to Portland, Malenfant said she learned that the captain was a commander during the Boston Marathon bombing and subsequent manhunt.

“He is a humble, inspiring, kind man,” Malenfant wrote. “I am blessed and honored to have spent a car ride with such an amazing national hero. Thank you, Captain Kelley McCormick.”

The Facebook post has been shared thousands of times since Saturday.

Boston Police Superintendent-in-Chief William Gross told The Globe “that’s not a one-time thing with Capt. McCormick.”

“He’s always giving. He’s a very free-spirited and giving individual. He has a great soul,” Gross said.

Malenfant said she hopes others share her story “to remind us all of the amazing men and women who make daily sacrifices to ensure our protection.”