How was the computer tagged as owned by jsmith? Would that name be the value of the User Name property or did you have a custom property that tagged the owner of a computer? This can be done as long as we know some property value uniquely associated with this system.
That User Name property in bigfix is only set if there is a user logged in, otherwise it will be None. It should only be set if it happened to be set at time of deletion.
Assuming your Computer Name and User Name properties are the same IDs as mine, you can use these queries:
select ComputerID,ResultsText from QUESTIONRESULTS where SiteID in (select SiteID from SITENAMEMAP where Sitename = 'ActionSite') AND AnalysisID = 27 AND ResultsText like 'Steve%'
select ComputerID,ResultsText from QUESTIONRESULTS where SiteID in (select SiteID from SITENAMEMAP where Sitename = 'ActionSite') AND AnalysisID = 4 AND ComputerID = 6140499
Run the first one replacing Steve with the desired username. It will return the computer IDs and usernames that match string. Then use the ComputerID from the first query in the 2nd query to get the computer name.