He was the one, she recounted months later, who assigned her first case file, the elderly man in Hunts Point. Nobody answered the door there on the first day, or the second, or the third, even though she knew someone was inside. Ms. Garcia checked back daily with her mentor for advice. Travel light and reduce the risk of losing your case files, he said. No heels — wear comfortable shoes. Look at how people dress and keep up their rooms to understand their state of mind. Listen for turns of phrase that suggest involvement with drugs. In most apartment buildings, the porter or super knows everyone’s business. Make friends, and he’ll open up doors.

She finally got the old man to let her inside. He was born and raised in Puerto Rico and came to New York years ago. The doctors wanted to do a lot of tests, but he didn’t see the use. It’s my time, he told her. She persuaded him to go anyway, but after a day of poking and prodding, the diagnosis was grim.

She went back to Mr. Chambers, who relayed more tricks of the trade. Ask him, “How are your children?” They live in Florida, the man replied. He hadn’t talked to them in a long time. He felt that he hadn’t been the best father. His emergency contact number, for his son, was disconnected. But Ms. Garcia found a daughter living in Orlando, who got her father a cellphone and helped him keep appointments. Things went better for a while.

Ms. Garcia took on more cases as her apprenticeship continued. She got two raises, bringing her salary up to $42,000 per year. This is a hallmark of the apprentice system. Unlike interns, who are often exploited by employers, apprentices are paid more as they advance in experience and skill.