WILLIAM TYRRELL’S FOSTER MOTHER NAMED AS PERSON OF INTEREST

William Tyrrell was last seen at his foster grandmother's house in Kendall in 2014. (AAP)

William Tyrrell’s foster mother has been named as the person of interest in the renewed investigation.

It comes as Strike Force Rosann detectives returned to the Kendall area this week to conduct further inquiries and search operations.

Yesterday officers concentrated on the garden bed below a balcony at the Benaroon Drive property, where the young boy was reportedly last seen alive.

Using luminol and a cadaver dog, they are looking into the possibility William fell from the second-storey.

Police have also seized a vehicle which formerly belonged to the young boy’s foster grandmother for forensic examination.

The Mazda was taken from a home at Gymea in south Sydney on Tuesday last week, as part of ongoing investigations into the 2014 disappearance of the three-year-old.

Analysis is expected to take several weeks.