A Bronx prosecutor abruptly resigned after he was caught on video allegedly attempting to meet a young boy he communicated with online, according to a clip produced by internet vigilantes who expose wannabe child predators. William C.C. Kemp-Neal, 30, quit his post in the Bronx District Attorney’s office four days after the group Dads Against Predators posted footage of him filmed in the parking lot of the Target on East Sandford Boulevard in Mount Vernon. In the clip taken July 8 at around 8:30 p.m., the video vigilantes approach a man identified as Kemp-Neal, asking if he’s Marcus. Almost immediately,...