The most direct clue about the gun used by Princess Sissi was a photograph that Gao Yang found with Dusselyev.
The leads about the two people in the photograph have already run out, so the third person, who took the photograph, becomes the key. However, this person has never been found, not even a trace. Since the two people in the photograph are KGB, it's a logical assumption that the person who took the photo is also KGB.
Now, the most important clue has emerged.
"I really didn't know I had broken into a KGB member's house. If I had known, I definitely wouldn't have dared to go."
Azaro muttered with a bitter face and said, "Focus on the key points, his specific address, and the homeowner's name."
Azaro smiled bitterly and said, "I remember the general area, but I really can't recall specifics like the house number. All the houses there look the same, even the furniture layout is similar, as they were all provided by the state."