Long before the complaints about shrieking parrots, many years before lawyers were hired and stern letters exchanged, and more than a decade before the Department of Justice literally turned the building into a federal case, the Rutherford, a 14-story co-op in the Gramercy Park neighborhood of Manhattan, was a pretty tranquil place to live.

At least it seemed that way to Charlotte Kullen. In late 1999, she was 26 and had already navigated a couple of difficult landlords as a renter in the city. When she closed on a small studio apartment on the Rutherford’s fifth floor, she felt relief.

“I was like, OK, peace and quiet and no problems,” she said in a recent interview. “It’d be an investment. And then, you know, in five years or whatever, I get married and I go have kids somewhere. In the meantime, I can paint my walls, I can decorate.”

Soon after arriving, she met her next-door neighbor, Meril Lesser, who had also recently moved in and was working on a master’s degree in psychology. The pair had plenty in common. They were both from New Jersey and roughly the same age. Both were deeply attached to their animals. Ms. Kullen owned a cat and eventually two papillon dogs, as well as a horse she kept in a barn in New Jersey. Ms. Lesser lived with two parrots.

The women quickly developed a friendship, one that started warmly enough. Together they went to bars and parties and sought a place in Manhattan’s social whirl, all the while trying to gain traction professionally. Ms. Kullen was laid off from a public relations firm, then cycled through a few different jobs before founding her own P.R. shop and working out of her apartment. Ms. Lesser was briefly a social worker and eventually started making jewelry, which she sold through an Etsy store.

Over the years, the neighbors shared meals, dating advice, pain relievers and the occasional holiday.