Hello As my title suggests, I just scanned 3 times, the same directory and I'm not finding a single trace of intrusion. There are other applications. Mz
You neither said what you are searching for nor why you are so confident that there is something that the software that you are using has not found nor which software you are using to search.
This answers one of the three questions that I asked you. Now please answer the other two. And I have no clue what you mean with: "one is throwing it in the background without this plant?" Maybe you can rephrase it. Btw. https://www.deepl.com/translator is currently the best translating service and it supports french to English translations as well, you might want to try that instead of bing or whatever you use now.
And regarding your question for alternative scan software: ClamAV, Maldet and for system wide scans: Lynis, rkhunter and chkrootkit
Is it ispp_scan we're throwing it in the background without this plant? via https://www.deepl.com/translator
Sorry, this sentence makes no sense. ispp_scan is a Malware scanner, it does not run in the background, you either run it in foreground as any normal shell app or you can run it as cronjob. And if an application runs in background or not is not related to the title "untraceable intrusion found" anyway, it makes no difference for the scan result if you run it in foreground as root user or as root cronjob. Rephrase your question in a way that its understandable what you mean.