Walter Mikac was in the darkest depths of grief, shock and anger.As he flew from Hobart to Melbourne — where his loved ones were to be buried — he decided to pen a letter to the then prime minister John Howard."As the person who lost his wife & two beautiful daughters at Port Arthur, I am writing to you to give you the strength to ensure no person in Australia ever has to suffer such a loss," he wrote.Days earlier — on Sunday, April 28, 1996 — Mr Mikac had been at a golf tournament in Tasmania when loud bangs...