This is a reference to Sunnī views on the legal status of homicide in situations of "precautionary secrecy" (taqiyya). Hossein Modarressi cites this source to show the various legal arguments and views pertaining to taqiyya, which is often misunderstood and additionally considered a sectarian issue.
This source is part of the Online Companion to Hossein Modarressi, Text and Interpretation: Imam Jaʿfar al-Ṣādiq and His Legacy in Islamic Law (Harvard University Press, 2022).