WASHINGTON (CNN) -- A top U.S. Customs and Border Protection employee was arrested Friday on suspicion of encouraging one of her cleaning ladies -- said to be an illegal immigrant -- to stay in the country.

An affidavit says Lorraine Henderson continued to employ a woman after being told she was an illegal immigrant.

Lorraine Henderson, whose job as Boston, Massachusetts-area port director for the agency included helping keep illegal immigrants out of the United States, was charged in federal court with harboring an illegal alien.

An affidavit alleges that the immigrant was one of three Brazilian women -- all said to have been in the United States illegally -- whom Henderson paid to clean her condominium in Salem, Massachusetts.

Customs employees had been advised in a memo not to employ illegal immigrants as domestic help, the affidavit says, and a fellow employee, to whom Henderson had recommended one of the women, learned that the woman was in the country illegally. The co-worker warned Henderson that she was violating the law by employing her, according to the affidavit.

But Henderson kept the woman on, and when the Customs and Border Protection co-worker learned that her warning had been ignored, she reported Henderson to a supervisor, the affidavit says.

Investigators then put a wire on the woman and recorded conversations in which Henderson told her she would see what she could do about her legal status, according to the affidavit.

"Yeah ... yeah, let me find out and see what ... you can do," Henderson said, according to the affidavit.

The affidavit says Henderson also left the cleaning lady a written list of questions, "including: did she enter the United States legally or illegally; where did she enter the United States; whether she had ever been convicted of a crime; and whether she had any legal alien relatives."

The affidavit says Henderson warned the woman to avoid deportation, because authorities would never allow her to return to the United States.

"Wow, wow, if you leave they won't let you back. ... You can't leave, don't leave ...'cause once you leave, you will never be back," it quotes her as saying.

Henderson was arrested Friday morning and was to make a court appearance in the afternoon. According to the U.S. attorney in Boston, Henderson could get 10 years in prison, three years of supervised release and a $250,000 fine if she is convicted.

Customs and Border Protection issued a statement saying that it "does not tolerate criminal misconduct by its employees, whether on or off duty; and we hold our officers and agents to the highest standards of professional conduct, and require our personnel to adhere to a culture of integrity and professionalism."

Calls to Henderson's home seeking comment went unanswered.

As Boston-area port director for the agency, Henderson has been responsible for overseeing all of the international ports of entry in Massachusetts, Connecticut and Rhode Island, including Boston's Logan International Airport.

CNN's Mike Ahlers and Eric Marrapodi contributed to this report.

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