William Tyrrell's foster-mother has been charged with giving false or misleading information to the NSW Crime Commission.
Detectives from Strike Force Rosann on Tuesday charged the 56-year-old, who cannot be named for legal reasons, with giving false or misleading information at a hearing.
Strike Force Rosann was set up to investigate William's disappearance.
He was last seen at his foster grandmother's home at Kendall, on the NSW Mid North Coast, in September 2014.
His foster-mother is due to appear in Sydney's Downing Centre court complex on May 24
On Friday, she was charged with stalking and intimidation offences.
In January, William's foster father was charged with giving false or misleading information to the NSW Crime Commission.
He has pleaded not guilty.
The pair are before the courts on a separate count of common assault against a child, which they have pleaded not guilty to.
The child is not William Tyrrell and the specific allegations against them are suppressed.
The couple has denied any wrongdoing.
Investigators did not find anything of note during a new search of bush, about a kilometre from the Benaroon Drive property where William was last seen, late last year.
