(CNN) -- A Florida mother has been arrested for her alleged part in attempting to sell her 8-week-old son, police said Tuesday.
Stephanie Bigbee Fleming, 22, is the third person charged in the case. Her mother, Patty Bigbee, 45, and her mother's boyfriend, Lawrence Works, 42, were arrested and charged last week.
Fleming was already incarcerated on unrelated charges.
Bigbee is accused of having approached a potential buyer in late October, offering to sell the infant for $75,000, the Florida Department of Law Enforcement (FDLE) said in a statement.
The would-be buyer then contacted authorities.
Together, they negotiated the price of the baby down to $30,000 and agreed to meet, the statement said. Bigbee and her boyfriend arranged the sale for last Friday, at which point officers swept in.
"They were in contact," said FDLE spokesman Keith Kameg about the mother and daughter. "And according to our investigation, they discussed the sale of the child. The birth mother was told by her mother that the sale price was $10,000."
Police say Fleming had agreed to receive $9,000 from the sale and that she planned to buy a new vehicle with the money.
The infant is currently in the custody of the Florida Department of Children and Families.
Fleming's bond was set at $50,000, while Bigbee's was put at $100,000. Works is being held on a $50,000 bond.