Agree with attorney Kimbrell. Your friend should be careful about waiving her Miranda right to remain silent. She has an absolute right not to incriminate herself, and, her decision to remain silent cannot be used against her. She should immediately seek the counsel of a criminal defense attorney whose communications with her are grounded in the preservation of attorney-client privilege (confidentiality).
This answer is offered for informational purposes only. It is not offered as, and does not constitute, legal advice. The answer presumes you are not currently represented by an attorney who knows your specific circumstances.
Always keep in mind that any voluntary statements that you make will be used to investigate and prosecute you. I agree with the two previous responses in that you should seek the advise of an attorney and invoke your Miranda rights.
Police are trained to extract self-incriminating statements. Lawyers are trained to prevent that. Never speak to the police regarding a criminal matter unless you have an attorney at your side.