It was known that the Harkonnens, the former rulers of Arrakis would leave many suicide troops behind.
9 seconds sound clip from the Dune (1984) movie soundboard.
You can hear this line at 00:56:09 in the Blu-ray version of the movie.
Quote context
[...]
- Hidden away within the rocks of these deserts on Arrakis are a people known as the Fremen.
- House Atreides took control of Arrakis, 63 standard days into the year 10191.
- Atreides' patrols were doubled.
- The Fremen have sent a message to you, Sire.
- No, I was instructed it was for you.
[...]