An Egyptian police officer has been detained on suspicion of killing a suspected member of the outlawed Muslim Brotherhood in hospital, the Interior Ministry has said.
The suspect was in custody and being treated in hospital for wounds suffered while he was allegedly planting explosives.
The ministry said in a statement late on Sunday that the man had provoked the policeman by insulting him. "Then the policeman lost control of his feelings," it said.
The army toppled president Mohamed Mursi of the Brotherhood in July 2013 after mass protests against his rule.
Security forces killed hundreds of Brotherhood supporters in the streets, arrested thousands of others and then jailed liberal activists charged with protesting without police permission.
The government has declared the Brotherhood a terrorist organisation and many of its top leaders have been put on trial. The movement says it is committed to peaceful activism.
Egypt's highest appeals court on Monday ordered the retrial of 12 Brotherhood supporters convicted of killing a police officer in 2013, in the violent upheaval that followed Mursi's overthrow, the state news agency MENA said.
In a separate case, a court jailed 66 Brotherhood supporters for three years on charges of attempted murder, membership of a terrorist organisation and possession of weapons.