wrote:
The New York Times of November 6, 1892 carries a story telling of the
shooting of Arthur Williams by Edward Treiter. Williams had been fired
by Steinitz, and Treiter was going to replace him. What more is known
about this tragic and violent incident? This was the first I had heard
of it, and I thought I would check out what is known before trying to
dig deeper on my own. I am no expert on Steinitz, especially from this
time period.

The matter is discussed on pages 159-160 of "The Steinitz Papers"
(McFarland & Co., 2000), edited by Kurt Lansdberger, where the names
are given as Treitel and N.W. Williams. The letter indicates Williams
shot Treitel, not the other way around.
A letter dated 4 November 1896, in which F.J. Lee looks back on the
incident, is quoted. In part it says:

"The American [i.e. Williams] used very often to amuse himself
shooting birds and rabbits in the wood, but one morning he returned to
the house from an early ramble and went into the bedroom with his gun,
which went off, and the German Secretary [i.e. Treitel] was killed.
This incident cause [sic] a great sensation at Upper Mont Clere, and
although the American firmly declared that it was an accident, he was
arrested on a charge of 'Manslaughter.'"

Lee says Williams was sentenced to "five or six years" imprisonment.
Steinitz and W.H.K. Pollock both testified at the trial, giving
"entirely different views" which led to "very seriuos differences" and
an irreparable rift between the two, the details of which are not made
clear.
After quoting Lee's letter, Landsberger says Treitel was not killed,
but lost an arm, in which case it would seem that assault, rather than
manslaughter, would have been the charge. Landsberger's treatment of
whole episode is rather hazy, and I too would be interested in more
details.
This was one of several tragic incidents for Steinitz in 1892 -- he
also lost his wife and a brother, and his magazine went under. The only
bright spot was winning his match with Chigorin.