Tiahleigh's mother Cindy Palmer's emotional statement about her daughter.

The biological mother of murdered schoolgirl Tiahleigh Palmer has given her first interview in months as police excavate the rural property of the foster family where the school girl lived for 11 months before her death.

Cindy Palmer addressed the media early this afternoon saying she was “extremely upset” that those entrusted with her 12-year-old daughter have now been accused of  taking her “innocence and spirit and her life.”

“The only comfort I can take from this situation is that they will never hurt another innocent child,” Ms Palmer told reporters in Brisbane.

“My other three children will now grow up without their sister and she will forever be an angel.

“I miss my daughter terribly every day and a piece of my heart is missing.”

Ms Palmer thanked those who provided the information which led Queensland Police to arrest Tiahleigh’s foster father Rick Thorburn who is charged with her murder.

His 19-year-old son, Trent, was charged with incest.

She also thanked the public and the media and asked them to respect the judicial process and refrain from speculating as the investigation continues.

“I will not let Tiahleigh’s death be in vain,” she said.