From Rabbi Burg’s Facebook page:

Dear Aish Family,
It is with great sorrow that I must inform you of the passing of Rav Reuven Biermacher HY”D, beloved Rebbe in the Aish HaTorah Spanish program. He spent the morning teaching Torah and was murdered on his way out of the Old City. May the Almighty strengthen us all during this difficult time and may he being all those responsible to justice.
With a broken heart,
Rabbi Steve Burg
Director General, Aish HaTorah