If someone commits suicide and the body isn't found, and no one reports them missing (or even if they do) its possible the death wouldn't be registered.
But most suicides ARE found and they'd be registered. It may be that the name is misrecorded or misindexed. This happens quite a lot. My own sister-in-law's marriage in 1991 has her surname misindexed as Searce instead of Pearce.
With Standley, I'd try Stanley, Stanly, Standlee, Standlea etc.