The following query in a report (http://k1000/adminui/report.php) will check the K1000 appliance for any emails that were sent to a user within a given time frame and for a given ticket number.
You will have to know the date range to search on and the user's id in the K1000 appliance. To find out the user's id you need to look at the URL underlying the link to their name from the list of users.
select * from HD_TICKET_CHANGE
LOCATE( '1234',NOTIFY_USERS ) >0 /* change 1234 to user's id*/
and MAILED =1 /*1 means they were sent an email*/
and TIMESTAMP > '1990-05-27' /*change starting date range here*/
and TIMESTAMP <'2200-05-27' /*change ending date range here*/
and HD_TICKET_ID IN (12221) /*remove this line if you want to search all tickets, or put in a comma-separate list of numbers for multiple tickets*/