On 24 April, the distinguished Palestinian astrophysicist Imad Ahmad Barghouthi was arrested and detained without charge by the Israeli military — for the second time in less than 18 months (see Nature http://doi.org/bk44; 2016). We protest against his imprisonment and renew the call for his release.

Once again, it was alleged that Barghouthi made statements on Facebook and on television in opposition to Israeli military attacks and occupation. Subsequent international pressure again contributed to a ruling by the military court of appeals a month later for his release (see go.nature.com/299v9nd). This has not happened. Barghouthi has instead been transferred to a facility run by Israel's internal security service, Shin Bet, for further interrogation.