Egypt's ousted president, Hosni Mubarak, and his two sons have pleaded "not guilty" to charges of murder and corruption, during a historic trial on Wednesday in the capital, Cairo.

The Mubaraks are being tried along with the former interior minister, Habib al-Adly, and six former security chiefs, nearly six months after the government was toppled in an 18-day popular uprising. A business executive and Mubarak confidant, Hussein Salem, is being tried in absentia.

Here is a brief look at the main figures on trial in Cairo.