ROCKFORD, Ill. — An Illinois man charged in a deadly stabbing and beating spree told police that he became paranoid after smoking marijuana that may have been laced with another drug, a chief prosecutor said Thursday.

Christian Soto, 22, has been charged with four counts of first-degree murder, seven counts attempted first-degree murder and two counts of home invasion in connection with a series of violent attacks in Rockford, authorities said at a news conference. He made his first court appearance Thursday and remains held without bond, according to Winnebago County jail records.

Soto, who lives in Rockford, is accused of killing four people and injuring seven others at multiple scenes in Rockford and Winnebago County on Wednesday afternoon. Rockford Mayor Tom McNamara identified the victims who were killed as Romona Schupbach, 63; Jacob Schupbach, 23; Jay Larson, 49; and Jenna Newcomb, 15.

"Our community has experienced such unthinkable tragedies this week," McNamara said at the news conference Thursday while holding back tears. "The trauma of this magnitude impacts all of us. These are dark days, but we as Rockfordians — we'll get through this."

Not all of the victims were stabbed and none had been shot, according to police. Four of the injured were treated and released, and three others remained hospitalized on Thursday.

Soto was arrested by police Wednesday. He will remain in Winnebago County Jail until at least April 2, when his detention hearing is scheduled.

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Chief prosecutor: Suspect told police he smoked marijuana laced with narcotic

The spree of violence included five crime scenes in a Rockford neighborhood and an area in Winnebago County, authorities said. The incident began with the killings of Jacob Schupbach and his mother, Romona Schupbach, according to Winnebago County State's Attorney J. Hanley.

Rockford police received a report of a person "being run over by a vehicle and possibly stabbed" outside of a home on Wednesday afternoon, Hanley said at the news conference Thursday. Responding officers conducted a welfare check and discovered the bodies of Jacob and Romona Schupbach, who appeared to have been stabbed.

Witnesses told police that they saw Jacob Schupbach “being chased across the street" by Soto, according to Hanley. Witnesses also saw Soto "in possession of an unknown possibly black object that he was hitting or stabbing Jacob with as he was lying on the ground," Hanley said.

Soto then entered a vehicle parked in the home's driveway and "proceeded to run over Jacob at the end of the driveway," Hanley added. Witnesses said they saw Jacob Schupbach get up and run back into the residence.

Soto then followed Jacob Schupbach into the home and fled "a short time later," Hanley said. Soto allegedy admitted to police after his arrest that he was friends with Jacob Schupbach and went to the 23-year-old's house to smoke marijuana.

Soto told police that "he believes the drugs provided to him by Jacob were 'laced' with an unknown narcotic," according to Hanley.

"Soto said he became paranoid after the drug usage," Hanley added. "He said he retrieved a knife from the kitchen at Jacob’s house and proceeded to stab Jacob and Ramona to death."

U.S. postal worker, teen girl on spring break among victims killed

After the Schupbachs were killed, Hanley said Soto fled the residence and attacked Larson, a U.S. postal worker. A witness said he saw Soto "battering" Larson and stabbing him repeatedly with a knife Soto retrieved from his vehicle, according to Hanley.

Soto then ran over Larson twice and fled the scene on foot, Hanley said. Responding officers discovered Larson with multiple stab wounds in the front yard of a home and he later died of his injuries at a hospital.

Larson was a 25-year veteran of the U.S. Postal Service, according to Ruth Mendoza, the inspector in charge for the U.S. Postal Inspection Service-Chicago.

"This tragedy occurred while Jay was doing his job, like many of us were at that exact time," Mendoza said at the news conference Thursday. "Jay was doing what he loved — serving his community, delivering mail to customers."

As police converged on the area, Soto broke into a house where teenage girls were home on spring break and were watching a movie, according to Hanley. Soto attacked the three girls, including killing Newcomb, with a softball bat that he found in the house.

“The girls ran to the corner of the bedroom. He started swinging the bat, striking all of the female victims,” Hanley said. Soto later fled the home.

"Jenna’s mom wants the community to know that Jenna died saving her sister and her friend and protecting them from further harm," McNamara said.