In the first letter, dated 31 July, soon after his father died, Ashbrook said he had been subject to psychological warfare when he served in the Navy between 1979 and 1983 and later in civilian jobs. In the second, he claimed he had been framed as a suspect in a series of murder cases and repeatedly lost jobs as a result.
Whatever the ultimate conclusions about Ashbrook and his motives, the church killings have prompted renewed soul-searching in the US about the availability of guns and frantic jockeying among election- conscious politicians not to be caught on the wrong side of the gun issue as the presidential primaries approach.
Each new mass shooting shifts public opinion a little further toward stricter laws, which favours the Democrats. The Republicans, with a few exceptions, reject new laws, calling at most for more effective enforcement of existing laws.
Well aware of the political risks of the gun control issue, the Texas Governor, George W Bush, who is favourite for the Republican presidential nomination, cut short a campaign visit to Michigan the morning after the shootings and returned home, saying the root of the problem was "evil", not guns. His wife, Laura, issued a statement cancelling her engagements for the rest of the week, saying she would be available to comfort the friends and families of the victims.
Vice-President Al Gore stressed the need for stricter gun controls and appealed to Congress to legislate. Earlier in the summer he had made the casting vote in the Senate on a Bill that would have made it more difficult for gun-buyers to avoid background checks, but the House rejected the Bill.
Even if the gunman was mentally ill, the emotive Fort Worth shootings have placed the National Rifle Association on the defensive. The chairman, Wayne LaPierre, said some people should not be allowed to keep guns and deplored lax enforcement of existing gun laws. The NRA is a big contributor to Republican campaign funds, and benefits from its patronage when the party is elected.