Two teenagers have been charged with murder in connection with the fatal shootings of five members of a family in Illinois. The victims were shot at three separate locations in East St. Louis, a city across the Mississippi River from St. Louis.

A 16-year-old boy will be prosecuted as an adult, while the case against a 15-year-old girl will start in juvenile court before a possible transfer to the St. Clair County criminal court, according to the county prosecutor’s office.

The shootings, described by police as a “targeted mass shooting,” occurred primarily over the weekend. Two additional individuals were wounded in the attacks. Illinois State Police Director Brendan Kelly reported that troopers stopped a vehicle and arrested the two teenagers on Sunday in a state park.

Court documents have not yet revealed a motive for the killings. However, Marcus May, the father of the 15-year-old girl, told the St. Louis Post-Dispatch that his daughter was upset with family members and planned the attacks with her boyfriend, Ja’ymeir Davis. May stated that he lost a nephew, two stepchildren, his mother, and a sister in the shootings. The victims ranged in age from 21 to 74.

Davis faces charges of murder and seven other crimes. It is not yet clear if he has retained legal counsel. A court hearing is pending for his case. One victim, Cherie May, who was Marcus May's sister, was reportedly shot days before the main series of shootings over the weekend, according to a court filing.