 Rex HarrisonArthur Groome | Arthur Groome |
 Lilli PalmerMary Groome | Mary Groome |
| TTania HealdSheila Groome | Sheila Groome |
| HHenrietta BarryRosemary Groome | Rosemary Groome |
| DDora SeveningMary's mother | Mary's mother |
| RRonald SimpsonMary's father | Mary's father |
 Anthony DawsonThe Man | The Man |
 Brenda De BanzieMrs Rogers | Mrs Rogers |
 Ballard BerkeleySupt. Maxey | Supt. Maxey |
 Raymond HuntleyChief Inspector Sullivan | Chief Inspector Sullivan |
 William SquireSergeant Cochcran | Sergeant Cochcran |
 Denis O'DeaSir Charles Morton | Sir Charles Morton |
 Anthony BushellClive Bedford | Clive Bedford |
| HHenry B. LonghurstJudge | Judge |
 Patricia CuttsRose Mallory | Rose Mallory |
 Meriel ForbesMarjorie Danns | Marjorie Danns |
| DDouglas JefferiesDr Conway | Dr Conway |
 Michael MedwinLeslie Scott | Leslie Scott |
 Colin GordonPound | Pound |
 Lionel MurtonJefferson | Jefferson |
 Eric PohlmannMr Polaris | Mr Polaris |
 Jenny LairdMrs Sims | Mrs Sims |
| FFrank TickleAlfred Tripp | Alfred Tripp |
| LLilli MolnarMrs Polaris | Mrs Polaris |
 Jill Bennett1st Murdered Girl | 1st Murdered Girl |
| FFletcher LightfootJury Foreman | Jury Foreman |
| AAnthony ShawClerk of the Court | Clerk of the Court |
| TTom MacaulayIronworks Manager | Ironworks Manager |
| RRichard LittledaleMr. Sims | Mr. Sims |
| TTony QuinnJoe | Joe |
