When Mathew Milewski’s new puppy, Molly, arrived by plane from Arkansas on Nov. 11, 2011, her paperwork included a note from the folks at Outback Beagles.

“I hope that she brings as much joy to you and your family as our dogs have brought us,’’ wrote breeder Sheila Rodgers “I wish her a long life of happiness and contentment.’’

The 4-month-old puppy got neither.

Police say Milewski, 25, a Sunny Isles Beach “high-frequency’’ trader, intentionally killed the 7-pound dog 24 hours after picking her up at Miami International Airport by dragging her across a parking lot until she bled, beating her with her leash, and slamming her into a hard surface.

One year later, witnesses say they’re still heartsick about what they saw and heard.

“Every day, I think about it,’’ said Paola Charry, 41, a nodding acquaintance of Milewski’s at The Crown, 4041 Collins Ave., where both lived at the time. “This for me was a nightmare. For everybody in the building it was a nightmare.’’

Charry told police that from her seventh-floor apartment, she heard Molly screaming, and from her balcony saw the 6-foot-1 Milewski hauling the spread-eagled pup across pavement.

Milewski, who has no criminal record, is facing third-degree felony animal cruelty charges in Miami-Dade Circuit Court, and if convicted, up to five years in prison and/or up to a $10,000 fine. Trial is set for Jan. 28 before Judge Yvonne Colodny.

In Milewski’s corner is David Macey, the attorney who represented another young man in a sensational animal abuse case: Tyler Hayes Weinman, 19 when he was accused of slaughtering 19 cats in South Miami-Dade in 2009.

Despite widely publicized, apparently damning circumstantial evidence, including necropsies by veterinarians from Miami-Dade Animal Services and the ASPCA, prosecutors dropped the charges after a defense expert concluded that a large animal killed some of the cats.

Weinman is suing several parties to the case.

Macey declined to say whether the same expert, Dr. Richard Stroud, is or will be involved in Milewski’s case.

Macey acknowledged that with Molly, “you can’t dispute there are injuries. How they occurred, whether or not it was a criminal act, is the question.’’

He added: “There are some things that have not come to light yet’’ in his client’s favor.

Milewski, arrested on Nov. 18, 2011, told Miami Beach police that he dropped the puppy in the shower.

“I don’t think I did anything wrong, other than the outcome was very poor because of the way the dog landed,’’ he said. “This was 100 percent an accident.’’

Molly arrived in Miami at 2:35 p.m. Nov. 11, 2011. American Airlines records show that Milewski picked her up at 3:14 p.m.

During a 20-minute taped interview with investigators, during which Milewski called Molly “it,’’ he said he found her on the Internet, but didn’t like her coat and considered returning her.

He took her to the apartment he shared with his then-boyfriend and another beagle named Macy. The next day, he said, he put an electric-shock collar and leash on Molly and walked her in the building’s parking lot.

Valet parker Carlos Gregorio told police he was bringing a car from the garage when he “heard a loud scream from a dog.’’ Thinking he’d hit an animal, Gregorio got out of the car. That’s when he saw Milewski “striking his dog with the leash,’’ he told police.