MILWAUKEE (WTAQ) - Some key testimony was expected Wednesday at a Milwaukee inquest into the death of Derek Williams.

The man’s mother was scheduled to take the stand, along with the Milwaukee police officers who were with the 22-year-old Williams when he died in their custody in 2011.

Williams had just been arrested for a street robbery when he gasped for air and collapsed. The squad car’s video was public last summer, and the inquest was sought after a medical examiner changed the cause of Williams’ death from natural causes to homicide.

The inquest was scheduled to run into next week.