The frantic search for a missing Northern California 6-year-old became a homicide investigation on Saturday when detectives discovered a child's burned body in a rural area, reports the Sacramento Bee.

The body of Jadianna Larsen was found about 100 miles away from her home.

The Sacramento County Sheriff's Department told ABC News that 25-year-old Juan Rivera was arrested on a murder charge early Saturday. Rivera is the boyfriend of Jadianna's mother. He is being held at the Sacramento County Main Jail without bail, according to the sheriff's department.

Sheriff's department Sgt. Lisa Bowman told the Sacramento Bee that Jadianna's mother -- whose identity was not disclosed -- was away undergoing an unspecified medical treatment at the time of the disappearance. She had left Jadianna in Rivera's care. Rivera is a registered drug offender, according to Bowman.

Rivera alerted police that Jadianna was missing on Thursday, May 28. He told investigators that he last saw her at 11 a.m. on Thursday in their apartment. He claimed that a seizure disorder caused him to suffer seizures for hours that day. Bowman said he told detectives that he woke up when his mother stopped by to check on him. They discovered Jadianna was missing and searched for 30 minutes before calling 911.

Since Thursday, sheriff's deputies, volunteers and search and rescue teams looked for the girl.

Jadianna's body was discovered by volunteer firefighters in the small town of Artois. Glenn County Sheriff Richard Warren said firefighters responded to a vegetation fire off a rural road on Thursday morning. A charred suitcase was found at the scene with a small female body inside, according to the Sacramento Valley Mirror.

Authorities are awaiting the body's identity confirmation and evidence tests from a county crime lab.

The sheriff's department said that Jadianna had not been at school for an entire week.

Rivera is scheduled to appear in court Tuesday, according to the Sacramento Bee.