Hi,
There are 2 ways you can achieve the same
1. Create an event monitor for deadlocks. This is the most effective way and it really helps in identifying the culprit statements.
2. Enable all monitoring at the instance level and take snapshots for the database, application and application details as well.
That would give you a clear indicator of what's happening and how to go about resolving your issue.
There have also been a lot of posts on the same in the forum and am sure you will benefit a lot by reading the same.
Cheers
Nitin.