Now that New York real estate heir Robert Durst is back in the “big house,” his original big house — the childhood mansion where he grew up before he morphed into an alleged cross-dressing killer — is on the market for $3.8 million.

The Normandy stone Tudor, at 27 Hampton Road in Scarsdale, comes with seven bedrooms, 6½ bathrooms and a three-car garage.

This is where young Robert says in HBO’s “The Jinx” that he watched his mom jump to her death. (For decades, others whisper that she may have been pushed.)

Surprisingly, the listing even mentions the “meticulously maintained” Ludowici-tiled roof.

The mansion is “on one of Fox Meadow’s most desirable tree-lined lanes,” according to the listing.

It features a sweeping marble staircase salvaged from the original Waldorf-Astoria, hardwood floors, beamed ceilings, five fireplaces and custom millwork.

There’s also a custom-designed chandelier, classic wood-paneled library and a solarium.