A female B.C. RCMP constable has filed a lawsuit against her former superior, claiming he sexually assaulted her then used his authority to intimidate her into a string of further encounters.

The first alleged assault took place in May 2009 after Staff Sgt. Travis Pearson invited Const. Susan Gastaldo to his home to discuss work, according to a claim filed Aug. 26 in B.C. Supreme Court.

Gastaldo claims Pearson "forcibly inflicted harmful and offensive sexual contact" with her, including anal intercourse, and ignored her repeated demands for him to stop.

He then allegedly used knowledge of Gastaldo's medical problems – which included memory loss, confusion and anxiety – to coerce her into another 20 sexual acts.

Pearson told her that if she came forward, "no one would believe her because he would tell them that she was mentally unstable and she was seeing doctors," according to the suit.

Gastaldo's lawyer, Walter Kosteckyj, said the effects of the alleged abuse on his client have been immense.

"She's been unable to return to work, she has trust issues, she suffers from increased anxiety, she's under the care of a psychologist," Kosteckyj told ctvbc.ca. "It's just been a life-changing experience."

Her superior allegedly said he would also tell her husband she was having an affair and then have her transferred to another detachment. She was told she would be a "feather in his cap," the claim says.

In August 2009, Gastaldo's husband found sexually charged messages between the two on her BlackBerry. The couple then filed a complaint with the RCMP, which was subsequently investigated by Vancouver police.

"Her husband has been very supportive of her from the beginning and remains so," Kosteckyj said, adding that Gastaldo felt the need to file the claim "to get started on her own healing."

The probe concluded that evidence did not support her claim, and no charges were recommended.

Instead, both Gastaldo and Pearson were charged with code of conduct offences, specifically misuse of RCMP technology and equipment.

The suit claims the Vancouver police investigation was mishandled, but does not name the department among the defendants. Gastaldo is seeking damages from Pearson, the RCMP and the province of British Columbia, however.

No statements of defense have been filed.