In the amusement park Eleanor and Leggett notice that police Inspector Ferris has followed them.
Then ... Behind them are two attractions, The Whip and The Skooter.
... from a vintage video ... the amusement park is long gone now but the same attractions can be seen (below) in a short vintage home movie taken at Ocean Park Pier in 1954.
Leggett suggests they split up to help avoid the police. He sends Eleanor off on the rollercoaster while he looks for her husband Frank but as she pulls away he carelessly mentions something only the killer would have known - the police had told it to Eleanor so she suddenly realizes with horror that Leggett is the killer. Because Frank had witnessed the crime his life is now in great jeopardy.
Below is a vintage photo of the rollercoaster at Ocean Park Pier and, in the movie, Eleanor, beside herself with fear and helpless to warn her husband, is tossed about on the hair-raising ride (click image to enlarge).
Leggett finds Frank - he knows of his weak heart and so attacks him hoping to provoke a heart attack. Eleanor hears a shot as she rushes over to them and fears the worst.
... but, phew!, it was Inspector Ferris who got there just in time and shot Leggett, bringing his investigation to a fitting end and leaving the way clear for Frank and Eleanor to be reunited.
Then ... The movie fades out with a shot of the amusement park's Laffing Sal cackling away (below) at the ironies of life.
... from a vintage video ... The home movie mentioned above also showed the same Laffing Sal (below). There's a change of clothing but the display, with mirrors, a beach ball and a dangling parrot, is the same.
... and Now, but a different one ... San Francisco's Playland-at-the-Beach amusement park also had a Laffing Sal display (as a result there are some, including Wikipedia, who mistakenly report that these scenes were filmed there). There were many Laffing Sals at funhouses across the country at that time, all built by the Philadelphia Toboggan Co. of Germantown, Pennsylvania in the 1930s. Playland has disappeared but its display (below) still cackles away today at the Musee Mecanique at Pier 45 in San Francisco.