ROCKFORD, Ill. (AP) — A judge on Monday ordered a psychiatric evaluation for a northern Illinois man charged with killing four people and injuring seven others by stabbing, beating and driving over them.

Winnebago County Judge Debra Schafer ordered the evaluation for Christian Soto when the 22-year-old man appeared in court by video link for a scheduled arraignment on charges of first-degree murder.

Soto’s arraignment now is scheduled for May 17.

Assistant State’s Attorney Ken LaRue said the case would go before a grand jury on Friday.

Soto’s attorney, Glenn Jazwiec, said he had no comment on the judge’s order.

Authorities have said Soto was behind a series of frenzied attacks on March 27 at multiple addresses in a Rockford neighborhood, but they haven’t determined a motive.

The Winnebago County coroner has identified those killed as 63-year-old Romona Schupbach; 23-year-old Jacob Schupbach; 49-year-old Jay Larson; and 15-year-old Jenna Newcomb.

Winnebago County State’s Attorney J. Hanley has said Soto told police after his arrest that he had smoked marijuana with Jacob Schupbach and believed the drugs “were laced with an unknown narcotic” that made him paranoid.

Soto first fatally stabbed Schupbach and his mother, then he beat, stabbed and used a truck to run over Larson, who was working as a mail carrier, authorities said. He next wounded three people inside one home, and beat Newcomb, her sister and a friend with a baseball bat inside another home, according to authorities. The attacks happened within a matter of minutes.

Winnebago County sheriff deputies arrested Soto as he fled from another home where he had stabbed a woman but had been slowed down by a driver who stopped to intervene, authorities said.