D.C. police are investigating whether a man will face criminal charges for shooting a pit bull that was attacking a child in his neighborhood.

The incident unfolded Sunday afternoon, after three pit bulls attacked an 11-year-old boy as he rode his bicycle through the Brightwood neighborhood of Northwest, according to a police report.

When the man, a neighbor, saw the boy being mauled by the dogs, he went inside his home and got a gun. The man killed one of the dogs. The gunfire attracted the attention of a police officer in the area near Eighth and Sheridan streets, where the attack occurred. The officer responded and shot the other two pit bulls as they continued to attack the boy.

The police report, which did not identify any of the people involved, said the boy suffered severe lacerations. The Washington Post, which first reported the details of the shooting, quoted the boy’s uncle as saying the boy was also shot in the foot.

Metropolitan Police Department spokeswoman Gwendolyn Crump said Wednesday that the entire case, including whether the man legally owned the gun he used to kill the dog, is under investigation.

While public opinion might be supportive of the man’s actions, he could still face significant charges depending on the outcome of the investigation, criminal defense attorney Daniel Gross said.

“I’ve seen cases where people used weapons in defense of others, but the U.S. attorney’s office is not always so understanding,” said Mr. Gross, who represents many clients charged with firearms-related crimes in the District. “There are certain defenses one could try, like self-defense or defense of others, but that wouldn’t really go to whether they charge you.”

The man could face a host of charges depending on the specifics of the case, including whether the gun used is a registered firearm that the man was legally permitted to own, Mr. Gross said. Possession of an unregistered firearm or ammunition is punishable by up to one year in prison and a $1,000 fine, and determining whether the man legally possessed the gun used will likely have greater bearing on the way the case is handled, Mr. Gross said.

Low-level unregistered firearms and ammunitions charges generally are prosecuted by the D.C. office of the attorney general, but additional charges could mean the case is bumped up to the U.S. attorney’s office.

“In this case, it would likely be the U.S. attorney’s office, and their discretion is sometimes less than local prosecutors,” Mr. Gross said.

Also to be taken into consideration is whether the man was within his property line when he fired the weapon — a small but significant distinction. Mr. Gross said it could mean the difference in whether he could be charged with carrying a pistol without a license.

On Sept. 8, Mr. Brinkley says he intended to drop his wife and young children at the White House for a tour and then head to a shooting range to practice for the U.S. Marshals Service test. Just like Mr. Gregory, Mr. Brinkley called MPD in advance for guidance on how he could do this legally. Mr. Brinkley was told that the gun had to be unloaded and locked in the trunk, and he couldn’t park the car and walk around.

Unlike Mr. Gregory, Mr. Brinkley followed the police orders by placing his Glock 22 in a box with a big padlock in the trunk of his Dodge Charger. The two ordinary, 15-round magazines were not in the gun, and he did not have any ammunition with him.

As he was dropping off his family at 11 a.m. on the corner of Pennsylvania Avenue, Mr. Brinkley stopped to ask a Secret Service officer whether his wife could take the baby’s car seat into the White House. The officer saw Mr. Brinkley had an empty holster, which kicked off a traffic stop that ended in a search of the Charger’s trunk. Mr. Brinkley was booked on two counts of “high capacity” magazine possession (these are ordinary magazines nearly everywhere else in the country) and one count of possessing an unregistered gun.

Despite the evidence Mr. Brinkley had been legally transporting the gun, his attorney Richard Gardiner said the D.C. Office of the Attorney General “wouldn’t drop it.” This is the same office now showing apparent reluctance to charge Mr. Gregory.

Mr. Brinkley refused to take a plea bargain and admit guilt, so the matter went to trial Dec. 4. The judge sided with Mr. Brinkley, saying he had met the burden of proof that he was legally transporting. Mr. Brinkley was found not guilty on all firearms-related charges, including for the “high-capacity” magazines, and he was left with a $50 traffic ticket.

Secret Service spokesman Ed Donovan told The Washington Times, “We feel it was a valid arrest, and the appropriate charges were brought.” Moments later, a spokesman for the D.C. attorney general's office, Ted Gest, called and provided the exact same quote. Mr. Gest added that, despite Mr. Brinkley’s acquittal, the ruling “doesn’t mean the judge is right, and we’re wrong.”