The differences in the hearings into the deaths of two slain police and their killer were mostly reassuring and respectful, but one threatens to ignite conspiracy theorists.

Inquests into the deaths of double murderer Dezi Freeman and the police officers he killed will begin today.

The coronial inquest will start into the deaths of police officers Neal Thompson and Vadim de Waart-Hottart and the man who murdered them, Dezi Freeman.