Kostya: Your theory was correct, Nikita. The killer has been killing two people per day with cocaine, and the drug was altering the perceived time of death.

Detective Andrei said he was able to talk to the man who found the bodies, but the man didn't give us much more information.

Additionally, Detective Andrei thinks we are dealing with a pair of killers.

Nikita: With all due respect, sir, I don't think it was a duo. The detective is wrong.

Kostya: How can you be certain?

Nikita: Because I think I know who it is.

Kostya: I was just going to ask you if you had more information for me... but I guess you've already solved it?

Nikita: Indeed, I have.

Kostya: Let's hear it.

From the initial deduction, I was able to narrow in on a prime suspect.