It was a dog of a day for Brooklyn pit bull owners. One man was arrested after throwing his family’s dog out a window to the dog’s death. Another man was arrested, in a separate and unrelated case, after neglecting to tend to his dog’s broken leg, law enforcement officials said.

At 8:05 a.m. yesterday, police received a tip from an anonymous female caller that there was a domestic scuffle involving an animal in an apartment on Saint Marks Avenue in Crown Heights, where Alan Decosta, 34, and his mother, Sonia Reyes, 48, reside, police said.The violence allegedly stemmed from an altercation between the mother and son. Mr. Decosta had been eating food from a bowl when Ms. Reyes allegedly pushed the bowl away from him. He was allegedly convinced his mother was going to give his food to their female pit bull, Gemini, and officials said Mr. Decosta lashed out at Ms. Reyes, grabbing her by the neck, punching her numerous times, and then striking her with a vacuum cleaner. Mr. Decosta then allegedly picked up Gemini, a brown and white dog that weighed about 55 pounds, and threw her out of their fifth-story window.

Ms. Reyes was treated at Interfaith Medical Center for back and head injuries, police said.

A necropsy, or animal autopsy, will be performed on the dog at the American Society for the Prevention of Cruelty to Animals animal hospital on East 96th Street in Manhattan, the spokesman for the ASPCA, Joseph Pantangelo, said.

Charges were pending as of early last night.

In the other case, ASPCA agents arrested Keith Callahan, 39, in Canarsie yesterday for misdemeanor animal cruelty and resisting arrest, Mr. Pantangelo said. The abuse dates back to September, when agents visited Mr. Callahan’s home on East 91st Street to investigate allegations of animal abuse. They found his six-month-old brown male pit bull – whose name was not immediately available – tied to a tree in Mr. Callahan’s backyard, holding his left hind leg in the air, authorities said. The agents determined that the dog’s leg had been broken for a couple of weeks, said Mr. Pantangelo, who is also a special agent for the ASPCA. Mr. Callahan was arrested for failing to bring his pet to a veterinarian.

The cause of the break remained unclear. “He would not provide us with any details about how the pet’s leg came to be broken,” Mr. Pantangelo said.

A metal plate was put into the puppy’s leg to mend the two broken bones. He is recovering at the ASPCA.

The arrest of Mr. Callahan, who has three prior arrests for assault, did not come until yesterday because investigators needed time to locate the suspect, conduct interviews with witnesses, and wait for a report on the dog’s medical condition, Mr. Pantangelo said.

The ASPCA’s Humane Law Enforcement Department, which investigates crimes against the city’s animals, had removed 239 unsafe animals from city homes this year, as of November 3, Mr. Pantangelo said. While the majority of those pets are dogs or cats, the figure includes swans, possums, and roosters.