The father of Pakistan's atomic bomb and a proponent of nuclear proliferation, Abdul Qadeer Khan, died Sunday at the age of 85 after a lengthy battle with COVID-19. He was a figure mired in controversy who launched Pakistan's nuclear weapons program, but also admitted to sharing nuclear technology secrets with Iran, Libya, and North Korea. Nick Schifrin reports. PBS NewsHour is supported by - https://www.pbs.org/newshour/about/funders