“There’s not a lot of rocket science to this. They’re going to be looking to discredit her,” said John Cutter, vice president of the investigative firm Beau Dietl & Associates and a retired New York Police Department top official.

Mr. Strauss-Kahn’s defense team has hired Guidepost Solutions to handle at least part of the investigative duties. Guidepost was founded by Bart Schwartz, former chief of the Criminal Division in the Manhattan U.S. Attorney’s office. Last year, the company acquired SafirRosetti, the investigative firm co-founded by former NYPD Police Chief Howard Safir. Guidepost didn’t respond to calls seeking confirmation that it was working on the case. Investigators who spoke to The Wall Street Journal said the defense investigation just of the maid could easily cost half a million dollars or more.

For those accused of a serious crime and who have the money to afford it, these type of investigations of the alleged victim have become commonplace; the goal is to make the accuser end up as the accused.

“When you have money you can put up a good defense for what should be indefensible,” said Anne Seymour, who works at Justice Solutions in Washington, D.C., and has worked as a victim’s advocate for the past 29 years.