When the contempt of court proceedings against Maricopa County Sheriff Joe Arpaio resume Tuesday, the sheriff's former lawyer Tim Casey is expected to be called as a witness.

Arpaio and four others are facing civil contempt of court for repeatedly violating U.S. District Court Judge Murray Snow’s orders in a racial profiling case. Tim Casey withdrew from representing Arpaio in that case last November, a year and a half after Snow ruled against the sheriff and found the department had discriminated against Latino drivers.

Casey later withdrew from the other suits in which he represented Arpaio as well.

It is unusual for a lawyer to have to testify about a former client, but Snow ruled the attorney-client privilege was waived on certain topics.

Plaintiffs' lawyers are expected to ask Casey about the sheriff’s office’s failure to implement the judge’s 2011 pre-trial order to stop detaining suspected unauthorized immigrants just on the basis of their immigration status.

Last week the sheriff’s chief deputy, Jerry Sheridan, testified he had no memory of meeting Casey and didn't remember hearing about the 2011 order for years after it was issued. A big question will be whether Casey will confirm or deny the accounts given by the chief deputy and others.

Casey may also be questioned about the sheriff’s use of a confidential informant who seemingly launched an investigation into the judge in the case.

Over the weekend the plaintiffs' lawyers filed a subpoena to a sheriff’s posse member requesting more documents and emails related to that confidential informant’s work for the sheriff.