KALAMAZOO, Mich. (AP) — The size of the jury pool could delay the start of testimony in the high-profile trial of a man who is charged with killing six strangers in southwestern Michigan.

Jason Dalton is charged with murder and attempted murder. He’s accused of shooting eight people in three locations in the Kalamazoo area in 2016, in between picking up riders for Uber.

Prospective jurors reported to court Thursday. Trial testimony was scheduled to start Monday, but assistant prosecutor Scott Brower says it could slip to Tuesday.

The process so far has been closed to reporters.

After Dalton’s arrest, police quoted him as saying a “devil figure” on Uber’s app was controlling him on the day of the shootings. Dalton has been found competent to stand trial.