By Tim Prudente From The Baltimore Sun BALTIMORE—Even in a city hardened to senseless violence, the killing of Jacquelyn Smith was shocking. The 54-year-old engineer at Aberdeen Proving Ground was stabbed in her chest while driving with her husband and stepdaughter through a desolate stretch of East Baltimore three years ago. Her husband told police Jacquelyn had passed $10 out the window to a couple panhandling with a baby, but that they snatched her necklace, stole the wallet from her lap and stabbed her repeatedly. Her husband drove her to a hospital and told police Jacquelyn was fatally wounded during an act of charity—three weeks before Christmas 2018, no less. The crime alarmed people across the country. “This story struck my heart. I’ve done this a 1k times. But will think twice before ever doing again,” Oprah Winfrey wrote online about Jacquelyn’s act of charity. Only detectives found none of …