When Erin Piacenti walked into Bank of America on Monday after five months on maternity leave, she found pink daisies sitting on her desk. Welcome signs were strung around the office she shared with a few teammates. Piacenti showed them photos of Madison, her newborn daughter, before settling in to read case law.

That afternoon, Piacenti was fatally stabbed in Times Square in what police described as an unprovoked attack. She was 32.

Though Piacenti only started as a vice president in the firm’s Americas Business Selection and Conflicts group around 18 months ago, she’d already made an impact on the small team. Hallie Ziesmer, the head of the…