On Saturday, Sarah Thalhammer celebrated her graduation from North Babylon High School on Long Island. In attendance were her proud friends and family and another very special individual, Officer Matthew DeMatteo, without whom Thalhammer may never have able to accept her diploma.

Six years ago, an 11-year-old Thalhammer was walking a friend’s dog when the animal dragged her onto the ice-covered Great South Bay. The flimsy coating soon gave way, and the girl found herself submerged in the frigid waters.

“I couldn’t really do much because the ice was so slippery,” Thalhammer said at the time of the incident. “He dragged me and we got to a spot where the ice was thin and I fell through.”

Fortunately, Officer DeMatteo quickly came to the girl’s rescue. He was able to pull her to safety—despite falling into the water himself—and the two made it back to shore. Since that fateful day, Thalhammer and her parents have considered DeMatteo to be a member of their family.

“It shows that miracles can happen,” Thalhammer’s mother Michaela told CBS2. “I’m very grateful for that.”

The Thalhammers have kept in close contact with DeMatteo over the years, and it was natural for the police officer to attend the ceremony. Dressed in his uniform and armed with a bouquet of flowers, he watched as Thalhammer took the stage in her cap and gown.

“For this story which could’ve easily become a tragedy, to be a success and have such a, you know, Disney ending if you will, it’s something I’ll remember for the rest of my life,” DeMatteo said. “She’s going into college and she’s going to do very great things. I’m very, very. very proud of her.”