A 15-year-old Illinois boy has pleaded guilty to involuntary manslaughter after he fatally shot a 13-year-old boy at a sleepover.

In the early morning hours of May 4, police in Centralia, Illinois, received a 911 call. Officers responding to the scene found 13-year-old Jaden Krauss with a gunshot wound to the head. He died later that morning.

The 15-year-old was charged, but the four other juveniles at the home were questioned and released.

The teen pleaded guilty in juvenile court on Tuesday. Because he is a minor, no additional details will be released on the plea. He has been remanded to the Franklin County Detention Center until his sentencing on June 26. PEOPLE was unable to find the name of an attorney authorized to speak on his behalf.

Authorities tell KSDK they are still investigating the shooting and that charges are possible against the other teens who were at the sleepover.

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“There’s still things we want answers to,” Police Chief Brian Atchison told the Belleville News Democrat. “This is still very much an active investigation.”

Jaden’s mother, Jaianna Grant, told KSDK that she believes that the 15-year-old did not act alone. “There’s other people that are responsible that also need to be investigated,” she said. “I want answers, I want answers.”

Grant also told the station her son didn’t usually hang out with the teens at the party, but that he knew them from school.

“Jaden was a student at the Centralia Junior High School, where he enjoyed running track,” the family wrote in an online obituary. “He also enjoyed playing video games, live streaming, and making videos for his YouTube Channel. Jaden had a passion for cooking and listening to music. He loved spending time with his girlfriend, Haylee, his family and friends.

“Jaden had a big heart and would accept anyone for who they were,” the obituary continues. “His legacy will live on through the organ donor recipients.”

The family has established a GoFundMe account to help cover expenses.