PARIS (AP) — The Syrian soldiers came first, at night, for the son, Patrick, a 20-year-old psychology student at Damascus University, and said they were taking him away for questioning.

They came back the next night for his father, Mazen.

Five years later, in 2018, death certificates from Syrian authorities confirmed to the Dabbagh family that the French-Syrian father and son would never come home again.

In a landmark trial, a Paris court is seeking this week to determine whether Syrian intelligence officials — the most senior to go on trial in a European court over crimes allegedly committed during the country’s civil war — were responsible for their disappearance and deaths.

The four-day hearings started Tuesday and are expected to air chilling allegations that President Bashar Assad’s government has widely used torture and arbitrary detentions to hold on to power during the conflict, now in its 14th year.