TEXAS (CBSDFW.COM)Texas EquuSearch, the volunteer group that looked for Caylee Anthony, has sued Casey Anthony to recoup their expenses.

The founder of the company, Tim Miller, says the 25-year-old mother knew her daughter was dead when Casey’s parents asked the group to help.

Miller says Texas EquuSearch responded with 4,200 volunteers and a month long search effort that cost more than $100,000.

Process server Bonnie Moore says she handed Casey Anthony the lawsuit papers Wednesday morning in her jail cell. “I have no idea what she was thinking,” Moore said of Casey’s demeanor. “She just asked if I had uh, given a copy to her attorney.”

EquuSearch is funded entirely by donations.

Last week Anthony was acquitted on first-degree murder, aggravated child abuse and aggravated manslaughter charges in the death of her daughter, Caylee.

Casey Anthony is scheduled to be released from jail Sunday, July 17.