Michelle Lodzinski of Port St. Lucie was arrested Wednesday. A grand jury in Middlesex County handed up an indictment last week, charging her with the murder of Timothy Wiltsey.
Lodzinski became a suspect soon after she reported her son missing. She said he disappeared May 25 at a carnival in Sayreville.
Police became suspicious when they were unable to find anyone who remembered seeing mother and son together at the carnival. The details of Lodzinski's story also changed.
Eleven months later, Timothy's skeletal remains were found in a swampy area in Raritan Center, an industrial park in Edison, N.J., where Lodzinski had worked.
"Following a routine, cold case review of the evidence and facts surrounding the disappearance and murder of Timothy Wiltsey, a new investigation was conducted and the matter was presented to the grand jury," Middlesex County Prosecutor Andrew Carey said in the statement.
Lodzinski was being held in Florida on $2 million bail pending extradition proceedings.
At the time of Timothy's disappearance, Lodzinski, then 23, was a single mother. After leaving New Jersey, she had two more children who live with her in Florida.
Edward Szkodny was a Sayreville police officer assigned to the carnival when Timothy vanished. He later rose to police chief and is now retired.
"It was a long time coming. Now we'll see that justice is served," he said.