That will be in the SQL Server error log.

Just to clarify something Anthony said. Data modifications (insert, update, delete and DDL) are stored in the tran log regardless of what recovery model you have, but the transaction log is not an audit log, it's not there to tell you who did what. It's there to allow rollbacks, database recovery and to guarantee durability of changes.

If you want an audit trail, you have to set one up.