Morsi's son said: Abdel Fattah el-Sisi and a number of other Egyptian officials are responsible for Mohammad Morsi's death.
Morsi, Egypt's first democratically elected president who was arrested after being overthrown in a military coup led by el-Sisi in 2013, died on Monday after collapsing inside his soundproof glass cage while on trial in a Cairo courtroom on espionage charges.
In a Twitter post on Thursday, Morsi's son, Abdullah, named a number of officials whom he called "partners" of el-Sisi "in killing the martyr president".
He particularly accused incumbent and former interior ministers Mahmoud Tawfiq and Magdy Abdel Ghaffar, respectively.
He also named judges Shirin Fahmy, Shaaban al-Shami and Ahmed Sabry, as well as Attorney General Nabil Sadek and Abbas Kamel, the head of the intelligence service.
Egyptian authorities have yet to comment on the claims by Morsi's son.