Challengers of North Carolina legislative districts say the computer files of a deceased Republican mapmaker show how GOP legislators approved boundary lines with illegal political bias.

The partisan gerrymandering trial’s first week in state court is complete. Democrats and the group Common Cause want judges to order 2017 House and Senate maps be redrawn for 2020.

Western Carolina University Professor Chris Cooper testified on Friday about maps from late redistricting guru Tom Hofeller’s files. Cooper says they show partisanship was “front and center” in Hofeller’s work, with lines benefiting one party at another’s expense.

Attorneys for GOP lawmakers say the lines were lawfully drawn and question how judges could evaluate political fairness. They’ll also present evidence in the trial, which is expected to last another week.