On Friday, the law firm of Steven J. Baum threw a Halloween party.The firm, which is located near Buffalo, is what is commonly referred to as a “foreclosure mill” firm, meaning it represents banks and mortgage servicers as they attempt to foreclose on homeowners and evict them from their homes. Steven J. Baum is, in fact, the largest such firm in New York; it represents virtually all the giant mortgage lenders, including Citigroup, JPMorgan Chase, Bank of America and Wells Fargo.

The party is the firm’s big annual bash. Employees wear Halloween costumes to the office, where they party until around noon, and then return to work, still in costume. I can’t tell you how people dressed for this year’s party, but I can tell you about last year’s.

That’s because a former employee of Steven J. Baum recently sent me snapshots of last year’s party. In an e-mail, she said that she wanted me to see them because they showed an appalling lack of compassion toward the homeowners — invariably poor and down on their luck — that the Baum firm had brought foreclosure proceedings against.

When we spoke later, she added that the snapshots are an accurate representation of the firm’s mind-set. “There is this really cavalier attitude,” she said. “It doesn’t matter that people are going to lose their homes.” Nor does the firm try to help people get mortgage modifications; the pressure, always, is to foreclose. I told her I wanted to post the photos on The Times’s Web site so that readers could see them. She agreed, but asked to remain anonymous because she said she fears retaliation.

Let me describe a few of the photos. In one, two Baum employees are dressed like homeless people. One is holding a bottle of liquor. The other has a sign around her neck that reads: “3rd party squatter. I lost my home and I was never served.” My source said that “I was never served” is meant to mock “the typical excuse” of the homeowner trying to evade a foreclosure proceeding.

A second picture shows a coffin with a picture of a woman whose eyes have been cut out. A sign on the coffin reads: “Rest in Peace. Crazy Susie.” The reference is to Susan Chana Lask, a lawyer who had filed a class-action suit against Steven J. Baum — and had posteda YouTube video denouncing the firm’s foreclosure practices. “She was a thorn in their side,” said my source.

A third photograph shows a corner of Baum’s office decorated to look like a row of foreclosed homes. Another shows a sign that reads, “Baum Estates” — needless to say, it’s also full of foreclosed houses. Most of the other pictures show either mock homeless camps or mock foreclosure signs — or both. My source told me that not every Baum department used the party to make fun of the troubled homeowners they made their living suing. But some clearly did. The adjective she’d used when she sent them to me — “appalling” — struck me as exactly right.

These pictures are hardly the first piece of evidence that the Baum firm treats homeowners shabbily — or that it uses dubious legal practices to do so. It is under investigation by the New York attorney general, Eric Schneiderman. It recently agreed to pay $2 million to resolve an investigation by the Department of Justice into whether the firm had “filed misleading pleadings, affidavits, and mortgage assignments in the state and federal courts in New York.” (In the press release announcing the settlement, Baum acknowledged only that “it occasionally made inadvertent errors.”)

MFY Legal Services, which defends homeowners, and Harwood Feffer, a large class-action firm, have filed a class-action suit claiming that Steven J. Baum has consistently failed to file certain papers that are necessary to allow for a state-mandated settlement conference that can lead to a modification. Judge Arthur Schack of the State Supreme Court in Brooklyn once described Baum’s foreclosure filings as “operating in a parallel mortgage universe, unrelated to the real universe.” (My source told me that one Baum employee dressed up as Judge Schack at a previous Halloween party.)

I saw the firm operate up close when I wrote several columns about Lilla Roberts, a 73-year-old homeowner who had spent three years in foreclosure hell. Although she had a steady income and was a good candidate for a modification, the Baum firm treated her mercilessly.

When I called a press spokesman for Steven J. Baum to ask about the photographs, he sent me a statement a few hours later. “It has been suggested that some employees dress in … attire that mocks or attempts to belittle the plight of those who have lost their homes,” the statement read. “Nothing could be further from the truth.” It described this column as “another attempt by The New York Times to attack our firm and our work.”

I encourage you to look at the photographs with this column on the Web. Then judge for yourself the veracity of Steven J. Baum’s denial.

SEE THE SLIDESHOW HERE