By John Clarke

ANNAPOLIS Md. (Reuters) - A Baltimore police officer facing felony animal cruelty charges after cutting the throat of a dog that bit a pregnant woman on the hand in June was legally authorized to euthanize the animal, his lawyer said on Thursday.

Criminal charges against 49-year-old Jeffrey Bolger are not supported by necessary probable cause, defense attorney Charles Curlett wrote in a letter to Baltimore City State's Attorney Gregg Bernstein asking that the case be dropped.

"This case involves a grim task carried out dutifully by an officer who was protecting a member of the public as he is sworn to do," Curlett wrote.

Bolger was arrested and charged with felony animal cruelty in June after he used a knife to cut the throat of a 7-year-old female Shar-Pei named Nala who was on the loose from home, killing the animal.

Curlett said in the letter Bolger performed a surgical incision that severed the dog's carotid artery. He also described Bolger as a 22-year police veteran with an "unblemished record of public service."

Police charging documents say that while the animal was restrained, Bolger slashed its throat, saying he would "gut" the dog.

He was suspended without pay, arrested and charged, police said. He has been a member of the Baltimore police since 1992 and is assigned to the Special Operations Section.

"It was a complete violation of protocol," police spokesman Eric Kowalczy told a news conference in June. "It's not often police speak out against one of their own, but we are all truly appalled."

Police said another officer, Thomas Schmidt, a Baltimore policeman since 1990, had been suspended over the case.

(Editing by Eric M. Johnson and Eric Walsh)