'The Spores' by David W. Rintels, George Eckstein, Ellis Kadison and Joel Kane

An alien named Tom Fessup poses as a salesman, but the briefcase that supposedly carries samples of his wares instead contains an experimental crop of alien spores - seedlings capable of producing a fully-grown alien creature after exposure to Earth’s atmosphere. David Vincent learns of the contents of the case and tails Fessup, but a gang of teenagers steal his suitcase and attempt to open it - can Vincent find them before they unwittingly unleash a new wave of alien invaders upon the world..?

Roy Thinnes (David Vincent), Gene Hackman (Tom Jessup), John Randolph (Ernie Goldhauer), Wayne Rogers (John Mattson), Mark Miller (Jack Palay), Patricia Smith (Sally Palay), James Gammon (Hal), Kevin Coughlin (Roy), Judee Morton (Mavis), Vince Howard (Frank), Brian Nash (Mike), Joel Davidson (Earl Garber), Christine Matchett (Elizabeth Garber), Norma Connolly (Waitress), Noam Pitlik (Jerry Burns), Stephen Liss (Archie), Robert Johnson (Sgt. Myons)
Directed by William Hale

A Quinn Martin Production

TX (US): 17th October 1967

Notes:
*Featuring David Vincent