The bullet marks speak for themselves. The mobs stood outside and fired into the windows. Some of them took possession of a building across the street and fired into the fourth and fifth story windows. There were no foreigners killed, although some of them were wounded. Some Russian officers who unwisely exposed themselves at the windows were shot and their bodies dragged out by the crowd.
For those who are following Rob Moshein and his saga in discovering his Easter European roots, here's another page from the Pallasart blog.
On either side of the nave of Hagia Sophia are great tympana, most of the mosaics there have been lost, but a few fathers of the church survive