How the Gilgo Beach Suspect Wielded Power in Brownstone Brooklyn

On most days, Mr. Heuermann made the culturally cosmic leap from his home in Massapequa Park to his Manhattan office on Fifth Avenue, where he was able to leverage an idiosyncratic power over people who might spend more money renovating their kitchens than it would cost to buy the ranch he lived in, now in such obvious disrepair. It is a kind of power distinct to life in New York, where the challenges of modernizing prewar apartments require time, money and typically the approval of a board entrusted with ensuring that plans to install a steam room, for example, will not cause the building to collapse or flood the apartment downstairs.

In his role as a consultant, Mr. Heuermann was often the person brought in to make these sorts of determinations. Through his long relationship with a management company, AMS, he was well known within the insular universe of Brooklyn Heights co-ops, finding himself in the apartments of investment bankers and lawyers, entertainment people and real-estate developers.

Like so many professions, architecture can be punishingly stratified, and Mr. Heuermann, who by all accounts was extremely knowledgeable about the city’s labyrinthine building codes, did not fall on the visionary side of the spectrum. But as a journeyman who held bureaucratic authority, he could veto the plans of architects with degrees from Yale and projects in Nantucket, who were retained by clients not accustomed to their ideas getting sidelined.

Last week a friend called to say that someone had been apprehended in the Gilgo Beach murders and that, however astonishingly, we both knew him. Mr. Heuermann had been in her apartment — deeply aggravating in the moment and intensely creepy in retrospect — and had been rude and dismissive when her architect called him out on a miscalculation he made. I also lived in a building that had used Mr. Heuermann and eventually severed the relationship, but it struck me that I could not remember anything about a person accused of such baroque violence, beyond my initial, shallow observation that he did not look like an architect.

A former board president, Kelly Parisi, who moved across the country several years ago, filled in the gaps about Mr. Heuermann’s time with the building when I reached out to her. During her own renovation, she told me, workers discovered some rotting beams between her apartment and the one above, a problem that Mr. Heuermann said needed to be remedied with drawings for the replacements, which he would produce. This struck the team working on her project as a kind of cheap hustle, given that the new beams could be installed without the sketches that would simply cost the building more money.