KISSIMMEE, Fla. — Investigators in the death of Madeline Soto say they are continuing to get more of their questions answered about who killed the 13-year-old and how she died in February but provided few other details Thursday during an update on the status of the case.

Police have interviewed individuals close to the girl and family members, including her mother, Jennifer Soto, Kissimmee Police Chief Betty Holland said.

The only person who has not cooperated so far has been Stephan Sterns, the boyfriend of Soto's mother and a person police have said is a key suspect. He is in jail in Osceola County on 60 charges unrelated to Soto's death and disappearance that include sexual battery, lewd and lascivious molestation and unlawful possession of materials depicting sexual performance by a child. He has not spoken to police.

Holland said law enforcement is still awaiting the medical examiner's report and other forensic evidence about the cause of Soto's death.

Police are continuing to piece together a timeline by speaking with individuals close to the deceased, but Holland would not speculate when someone would be charged with killing Soto or whether more than one person could be charged.

"During our investigation, we have interviewed many individuals. Each interview has been vital to our understanding of the case, Holland said. "We are reviewing all of the information we've received and are following up on every lead." 

She said, "Everyone that was close to Madeline is considered a suspect until we have proven otherwise."

Police will release details, as appropriate, to ensure the investigation won't be compromised, she said. 

"Our questions are being answered slowly but surely," Holland said. "For the integrity of the investigation, we have to keep things close until such time as we hold those accountable for her death."

Holland said they do not believe there were any victims other than Soto.

Spectrum News 13's Asher Wildman contributed to this report.