Arguments about the credibility of one witness, a former Suffolk County Police Department lieutenant, consumed much of the opening statements in the trial of former Suffolk County District Attorney Thomas Spota and his former unit chief Christopher McPartland in the Eastern District of New York on Thursday.

Spota and McPartland are charged with obstruction of justice and related offenses in connection with the concealment of a 2013 assault of a man arrested in Suffolk County after breaking into then-police chief James Burke’s car, according to federal prosecutors.