LOS ANGELES (KABC) -- A former Los Angeles County sheriff's deputy alleges that corruption is widespread in the sheriff's department from the top down.

Penelope Armstrong says her partner lied in court about being choked during a chaotic traffic stop, but then she lost her job when she told the truth.

Armstrong says she's a fourth generation member of law enforcement and was a rare female member working on the streets for the department's gang unit. She now believes the department is corrupt, sexist, and routinely covers up the truth.

In the incident that Armstrong says led to her firing, her partner apparently grabbed a woman and threw her against their squad car. The partner claims he was then choked by a man nearby. It's a claim Armstrong says he didn't bring up until hours afterwards.

"I don't think it ever happened," said Armstrong. "I think he's lying."

Armstrong refused to back up her partner's story in court. She said there was pressure put on her by the sheriff's department to lie. Armstrong eventually testified against her partner and says a jury sided with her, finding the man not guilty of the choking.

"I firmly believe that by telling the truth, I saved an innocent man from going to prison for several years. Whatever happens to me, whatever I lose, that to me is worth it," said Armstrong.

Armstrong, a 10-year veteran, was terminated.

"I believe the official reason was cowardice and lying," said Armstrong.

She and her attorney, Luis Carrillo, are filing a civil claim against the department.

"She was wrongfully terminated because she refused to go along with an officer's false version of events," said Carrillo.

Sheriff's spokesman Steve Whitmore wouldn't comment on the specifics of the case, but said, "Allegations are easy to make, evidence is harder. There's no evidence here."

Armstrong says she was targeted because she's a woman.

"Unfortunately, the sheriff's department still is run like the old boy's network," said Carrillo.

In the civil claim, Armstrong quotes fellow deputies saying things such as, "You are an embarrassment to females" or "Why don't you make yourself useful, go make a sandwich...You're worthless, you should trade your gun for an apron."

Whitmore said sexual harassment does not exist in the department.

"When this is all said and done and the facts come out, the department will be, in every aspect from top to bottom, exonerated," said Whitmore.

Armstrong said she understands why it's hard for people to stand up to a large department.

"They're big bullies and it's hard to fight a losing battle. But I'm passionate. I believe in right and wrong and I did the right thing," she said.

Armstrong wouldn't say how much money she's looking for in a potential civil lawsuit. Her attorney says he hopes her story prompts a federal civil rights investigation into what he calls repeated examples of excessive force by deputies.

http://abclocal.go.com/kabc/story?section=news/local/los_angeles&id=9144029