An explosion rocked a Cairo suburb
The explosion in the Cairo suburb of Maadi has also injured his wife and two children, Egypt's Interior Ministry said.
They said the man was a building guard in the leafy surburb popular with diplomats who was cleaning the property's garden when he found an "unidentified metallic object" which exploded when he picked it up.
Police cordons have been put up around the area as police investigate.
Earlier today Mubarak was released from the Maadi Military Hospital, in the same district as the explosion, where he has been detained for the past six years, his lawyer said.
There was no immediate claim of responsibility for the explosion and the cause is not yet known.
Mubarak at his 2015 embezzlement trial
The blast was in the Maadi suburb of Cairo where Hosni Mubarak was released from today
The former Egyptian leader was overthrown in 2011 and was the first leader to face trial following the Arab Spring uprisings which swept the region.
A top appeals court cleared Mubarak, 88, earlier this month on charges of killing protesters in the 2011 uprising which ended his 30-year rule.
He headed to his home in Heliopolis today and arrived safely, his lawyer said.
In 2015 Mubarak and his two sons were handed three year jails sentences in a retrial for embezzling millions of dollars' worth of state money to fund a lavish lifestyle which included upgrading their private residences in Cairo, the Red Sea coast and their family farm instead of using the cash to renovate and maintain presidential palaces.
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