Simply means she is currently being held by State authorities, most likely under some state arrest warrant or charges pending against her.
Kindly be advised that the answer above is only general in nature cannot be construed as legal advice, given that not enough facts are known. It is your responsibility to retain a lawyer to analyze the facts specific to your particular situation in order to give you specific advice. Specific answers will require cognizance of all pertinent facts about your case. Any answers offered on Avvo are of a general nature only, and are not meant to create an attorney-client relationship.
Mr. Shusterman's (former INS Trial Attorney, 1976-82) response to your question is general in nature, as not all the facts are known to him. You should retain an attorney experienced in immigration law to review all the facts in your case in order to receive advice specific to your case. Mr. Shusterman's statement above does not create an attorney/client relationship.
If she's in custody, it might be that they're charging her with state, federal, or immigration violations. It's hard to tell which just based on the information you've provided, but she's in trouble for sure if she's under marshall custody. Consider hiring an experienced immigration custody to help you fight her case and if you speak with her, advise her not to sign anything before being appraised of her rights, and always always always keep a copy of anything she's provided with in writing.
The answer given here is based solely on the facts provided, which may be incomplete, and is intended for general information only. It does not establish an attorney-client relationship, nor should it be relied upon for further legal action, which should only be taken after first having a consultation with an experienced, licensed attorney.