Detective Lennie Briscoe suggests that the carjacked vehicle is in a crate "on its way to Düsseldorf." Düsseldorf is the birthplace of Elisabeth Röhm, who plays Assistant District Attorney Serena Southerlyn.
This episode appears to be based on two separate cases/incidents:
- The 1998 Dr. Richard J. Schmidt case.
- The 2002-2004 SARS outbreak.
Jack Gwaltney has played three different characters over the course of the series:
- Episode 1.8 Poison Ivy (1990) - Officer Davis.
- Episode 8.3 Navy Blues (1997) - Jack Young.
- Episode 14.3 Patient Zero (2003) - Ian Hopkins.
P.J. Benjamin has played three different roles over the course of the series:
- Episode 5.10 House Counsel (1995) - Arthur Gibbons.
- Episode 12.1 Who Let the Dogs Out? (2001) - Dr. Paul Garrett.
- Episode 14.3 Patient Zero (2003) - Owen Franks.