The the API does not have any audit trail functionality. However you can use The Raiser's Edge front end query to find similar information. The Knowledgebase article below has the steps to accomplish this:

How to find records that were added or last changed by a particular user or on a specific date (from the RE front end)

Also, if you're interested in setting up an audit trail for future use, the following may be helpful: A SQL query on the RECORDS table can also show you which constituent records are marked with that user as last changed by:
select USR.NAME , REC.DATE_LAST_CHANGED, REC.FULL_NAME 
from RECORDS REC
left outer join USERS USR on REC.LAST_CHANGED_BY = USR.USER_ID
where USR.NAME = 'Supervisor'
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