The following message is given when the server resolves a deadlock situation:

Server: Msg 1205, Level 13, State 50, Line 1
Transaction (Process ID 55) was deadlocked on {lock} resources with another process and has been chosen as the deadlock victim. Rerun the transaction.

To see what was running in Process ID 55 (just an example), run immediately after the deadlock before the spid is recycled:

DBCC INPUTBUFFER(55)