City Comptroller John Liu has not been charged and is not expected to testify at his ex-aides' trial in federal court in Manhattan.

WSJ: Trial opens for aides of NYC mayoral hopeful

Court records show a psychologist is scheduled to testify at the hearing as to Loughner's current mental condition.

CNN: Attorneys for Loughner expected to enter new plea Tuesday

Used primarily in civil cases, meteorologists are called upon to testify in court as to how the weather influenced the dispute at hand.

FORBES: The World of Forensic Meteorology

At her court-martial, England will very likely testify on her own behalf -- and will very probably identify the person who, she says, ordered her to abuse prisoners.

CNN: Carter: The 'I followed orders' defense

As a punitive sanction, an appellate court ruled the girl cannot testify unless she shows her records to, at the very least, Racine Circuit Judge Eugene Gasiorkiewicz for a closed-door review.

FORBES: Billionaire Child Sex Case Heads To Supreme Court (18 Months After SC Johnson Heir Charged)

Earlier this month, a relative of witness M, who did not testify at last year's trial, swore an affidavit branding him a compulsive liar, the court heard.

BBC: Constable Stephen Carroll