The inconsolable son of Westchester real estate executive Steven Dym arrived home Monday to the house where his dad just days earlier killed the young man’s sister and mom before turning the shotgun on himself.

The grim homecoming came as new details emerged on Dym’s shady financial dealings — with allegations in one lawsuit alone that he stole $200,000 from buildings he managed.

Dym gunned down his daughter, Caroline, 18, and wife, Loretta, 50, on Friday in the Pound Ridge mansion. He then killed himself.

His only surviving child, Will — a 20-year-old student at the University of Southern California — returned from Los Angeles to visit the scene at his family’s Fox Hill Road home.

State Police said they were investigating whether the murder-suicide was related to the financial strain and the cloak-and-dagger lifestyle that Dym had been leading.

One suit filed by the owners of an East Village building in 2015 said Dym and his company, Gabriel Management, used the building’s account as a private piggy bank.

“The amount of money that has been unaccounted for and upon information and belief has been misappropriated by Gabriel and Dym over a five-year period is upon information and belief at least $200,000,” the suit reads.

He also skimmed money on tax bills or bank refinance fees and submitted fake invoices, according to the lawsuit.

Dym was supposed to give a deposition in the case last month, but it’s unclear if he showed up.

Steven and Loretta DymPatrick McMullan

Besides the two active lawsuits, Dym settled out of court with at least two other irate clients who alleged that he collected rent from tenants but didn’t always use it properly to pay the building’s bills.

The Post first revealed Dym was in Supreme Court last week over allegations he took $22,000 from a client who manages co-ops in Chelsea.

“We don’t know how much money is missing and we were in active discovery, ” said Richard Walsh, the lawyer attempting to track down any initial cash Dym had pocketed.

Besides cash, Dym allegedly stole financial records and refused to return them.

“We don’t know what happened to the books,” said Walsh. “He had a lot of different stories about where they were.”

A funeral Mass for the Dym family will be held Wednesday at 11 a.m. at St. Patrick’s Church in Bedford.