The mother of missing Orlando preschooler Caylee Anthony is now officially considered a suspect in her disappearance, Orange County police said.

Authorities have generally been referring to Casey Anthony as a "person of interest" in the case — but Capt. Angelo Nieves confirmed Thursday that has changed. The 22-year-old mother is now formally suspected in her toddler daughter's disappearance, Nieves' office told FOXNews.com.

The move comes after reams of pages of "discovery" — evidence documents including text message, voicemail and police interview transcripts — were released last week and police announced their belief last month that the missing child is dead.

Caylee was last seen in mid-June, when she was 2. Her third birthday came and went Aug. 9.

Click here for photos.

Click here for documents released in the case.

Her mother has still not been formally charged with anything related to her disappearance other than lying to investigators and child neglect and has repeatedly told officers she left Caylee with a baby sitter and doesn't know where she is.

Detectives say they don't believe her.

Meanwhile, a Thursday court date for Anthony to appear unrelated check fraud charges was postponed, MyFOXOrlando.com reported. The new date will be Oct. 14.

Earlier this week a woman with the same name as Caylee's alleged baby sitter, Zenaida Gonzalez, said Anthony had ruined her life. She is suing her for defamation.

Click here to watch the Gonzalez interview on MyFOXOrlando.com.

Anthony's attorneys say the sitter is a different Zenaida Gonzalez and called the lawsuit frivolous. They have lambasted police for their "leaks" in the case.

Click here for a timeline of the case.

Click here for more from MyFOXOrlando.com.

FOXNews.com's Catherine Donaldson-Evans contributed to this report.