What happened
The clerical-grade recruitment paper was leaked on WhatsApp; the state cancelled the exam and an SIT arrested the BSSC chairman (a senior IAS officer) along with several relatives and others, around 30 people in total.
What was done
Exam cancelled
Arrests / FIR
Official probe — SIT
Source
Primary reference The Tribune (PTI) ↗ https://www.tribuneindia.com/news/archive/nation/paper-leak-case-bihar-staff-service-commission-chairman-arrested-in-jharkhand-368898This entry summarises the linked report. Where the summary and the source disagree, the source wins — and please tell us.