DNA Replication Question?

From a hospital patient afflicted with a mysterious illness, you isolate and culture and then purify DNA from the culture. You find that the DNA sample obtained from the culture contains two different kinds of DNA; one was labeled as double-stranded human DNA and the other was labeled as single stranded viral DNA. However, a mix-up occurred and the labels were accidentally removed from the test tubes. How can you figure out which test tube contains which DNA?