You were right,as always,sonar732.
I marked both contacts in narrowband,designated S01 and S02.Classified them as Akulas and launched an UUV towards S02.The UUV detected no contacts at the bearing of S02 and I dropped it off.
Then,I calculated a TMA solution for S01,preset one MK-48 ADCAP for active homing,other for passive and launched both from the range of approximately 7000 yards.I was greatly surprised when one of those torpedoes hit and sank a Victor-III sub!There was a Victor-III,although narrowband identified 50 Hz signature as that of Akula-I.
Here is a screenshot showing that Victor-III was a bit far away from original narrowband S01 contact.
That under ice mission of Seawolf's campaign is unbelievable.There are several different subs,and you get different kills each time you play it.