Luigi Mangione, the man accused of fatally shooting United Healthcare CEO Brian Thompson in Manhattan a year ago this week, has appeared in court as his lawyers challenge the admissibility of key evidence in his case.
Mr Mangione, 27, has pleaded not guilty to both state and federal murder charges, which carry the possibility of the death penalty.
The pre-trial hearing could last several days, as defence attorneys are expected to call a host of witnesses, including from Pennsylvania, where he was arrested at a McDonald's.
In September a judge threw out state terrorism-related murder charges against Mr Mangione, arguing prosecutors had failed to establish evidence to justify them.
Mr Mangione's legal team is now hoping to convince a judge to exclude evidence including a gun and a notebook in which prosecutors say he set out a motive.
