Christina Korbe, 40, was arraigned early Thursday on a homicide charge in the shooting death of Special Agent Sam Hicks on Wednesday.
Korbe told investigators she thought her home was being burglarized and that she was shooting at an intruder.
Hicks and other law enforcement officers went to Korbe's home to serve a warrant on her husband, Robert, as part of a drug sweep.
Christina Korbe called 911 during the raid and said her house was being robbed and that she had fired at a burglar. She was arrested while still on the phone with an emergency dispatcher.
She later told investigators that she never heard police announce themselves, according to a criminal complaint.
CBS station KDKA in Pittsburgh reports that local residents who know the Korbes were shocked to learn of the raid and shooting.
The Korbes often dined at the restaurant next door to their family-owned convenience store on Main Street in Sharpsburg, according to KDKA.
"It's real hard to understand," said one woman who works in the restaurant. "It's just something, you know, when I met her here, you know - very nice - when she had a meal here."
The Allegheny County Police Department, which filed the homicide charge and participated in the raid with the FBI and the Drug Enforcement Administration, said the team that went to the home to arrest Korbe's husband knocked on the door around 6 a.m. and shouted "police!" several times.
Hicks was shot almost as soon as he entered, shouting "I'm hit!" before falling to the ground, police said. He was wearing a bulletproof vest, but was wounded just above it, authorities said.
Christina Korbe was with her 10-year-old daughter and 5-year-old son when agents arrived and may have feared for their safety, said her attorney, Sumner Parker.
"It became very chaotic and confusing and based on some other things taking place. ... My client may have taken actions that she thought was appropriate and ultimately called 911 to get local police to her house based on what she thought was happening," Parker told The Associated Press.
Robert Korbe, however, knew police were at his door, according to a police affidavit.
He told investigators that, when he heard and saw agents pounding on his front door, he ran to the basement to retrieve some cocaine and pour it down a drain, according to the criminal complaint. He allegedly told investigators that, when he was finished, he was surprised that no police were in the basement, so he ran into his backyard, where he was arrested.
Parker, who also represents Robert Korbe, said he can't explain why the husband appeared to realize police were raiding his home when his wife didn't.
Robert Korbe, 39, was one of 35 people charged Wednesday in the 27-count indictment that accuses the defendants of conspiring to traffic cocaine and crack from October 2007 through September. Christina Korbe was not named in the indictment.
FBI Director Robert Mueller III was in Pittsburgh on Thursday to meet privately with Hicks' family and colleagues.