The first 911 callers early on Friday reported seeing people fall from high up in the Gotham Hotel in Midtown Manhattan. A man would later tell detectives that he heard two crashing sounds — one after another — and followed them to the shattered bodies of a woman and a boy on the hotel’s second-story landing.

“He heard two loud noises and his attention was drawn to that, and he discovered these two deceased individuals,” Assistant Chief William Aubry, commander of Manhattan South detectives, said at a news conference.

Investigators soon learned that the woman was 47-year-old Stephanie Nicolai, a former Playboy model and author who had been enmeshed in a custody dispute over the child found dead at her side: her 7-year-old son, Vincent.

As the police began an investigation into the deaths, searching for witnesses and seeking video evidence to help piece together the events, they said that no assailants were being sought.

But one of the emerging theories was that Ms. Nicolai “may have pushed the son off first and then jumped,” said a law enforcement official who spoke on the condition of anonymity to discuss an ongoing investigation. Beyond the fact that the bodies seemed to have fallen separately, the official said, a “high railing” — perhaps somewhat of an impediment to a young boy acting alone — had to be surmounted before the fall.

The deaths occurred at about 8:15 a.m., Chief Aubry said, at a hotel that describes itself as a “boutique” destination with “67 spacious suites and hotel rooms with balconies across 25 floors,” and a Wolfgang’s Steakhouse embedded as a commercial anchor.

Indeed, as investigators and reporters clogged the sidewalk outside the high-rise hotel on East 46th Street, between Madison and Fifth Avenues, passers-by, including employees of nearby businesses, thought a celebrity had been sighted. Many expressed shock and sadness to learn that the attention was over the death of a woman and her son.

By early afternoon, no suicide note had been discovered, the police said. And a motive for the deaths was still being investigated, said the law enforcement official. Yet details about the victims’ past began coming into focus.

Raoul Lionel Felder, a former lawyer for the woman — whom he referred to as Stephanie Adams, the name she used in her November 1992 Playboy appearance — said he last spoke with her about three months ago, and was concerned about her mental health.

“She talked about leaving the country,” Mr. Felder said.

He said that a judge recently told her she could not take her son to Europe, as she had wanted. According to the law enforcement official, it appeared that Ms. Nicolai had been asked on Thursday to relinquish her son’s passport.

Though Mr. Felder said he did not represent Ms. Nicolai in recent legal proceedings, he believed she had unrealistic expectations about her divorce and custody options.

“I felt she needed help in a different area,” Mr. Felder said. “I’d been her friend for 20 years.”

This week, Mr. Felder said, a notice came addressed to him and his former client from the city’s child welfare agency. It appeared that she had made an inquiry with the agency to see if there were any open investigations, he said, but there were none. Such inquiries to the agency, the Administration for Children’s Services, are common in contentious divorces where a parent makes a claim against another.

Sanford A. Rubenstein, a lawyer who represented Ms. Nicolai in a case against the Police Department, recalled how a civil jury in Manhattan ruled in 2012 that she had been the victim of excessive force and awarded her $1.2 million — a sum a judge later reduced around $400,000. Four years later, Mr. Rubenstein said, the Police Department granted her a gun permit after initially denying it.

“She had felt at the time that the actions of the police were in part as a result of her being successful in the lawsuit against them,” Mr. Rubenstein said. He said she called him often as recently as “a few months ago,” to speak about her businesses or “the matrimonial matter or the custody matter” that she was confronting. He said he believed she was separated from her husband.

“She really loved that boy,” Mr. Rubenstein said of the 7-year-old. “During the trial, she would bring the little boy with her to court every day and the judge gave her a separate room to sit in with the child. She was inseparable from that child.”

Chief Aubry said that the two had checked into the Gotham Hotel at about 6 p.m. on Thursday. They were given a suite on the 25th floor, and it did not appear anyone else had been staying in the room with them, the police said.

The deaths came about 14 hours later. Though the initial 911 callers said they believed someone had fallen, the police, in a flurry of follow-up radio communications, referred to the victims as jumpers — police jargon for those who commit suicide.

The mother and son were both clothed, the police said. After they fell, the two came to rest on the roof of the second-floor balcony in the hotel’s rear courtyard. No one on the balcony, or on the street below, was injured, the police said.

Reflecting on the loss, Mr. Felder said that the boy, whom he called “Vince,” was being home-schooled by his mother.

Inside his office, Mr. Felder said, is a hand-carved statue of Spiderman.

“He used to play with it,” Mr. Felder said of the boy, who would have turned 8 in June. “He was a very bright, smart boy. Cute. Cute as a button.”

Mr. Felder said he was in disbelief.

“At the end of the life, there’s a choice you can make, but how she could do this to her child?” he said. “She was more wrapped up than any mother I saw.”