> Is there a source for this?
For the claim that Slim had criminal ties? No, not really.
The immediate source was this tweet, which asserted, without any clear basis, that Slim has "significant ties to the drug cartels in Mexico": https://x.com/wallstreetmav/status/1882255277551972619
The linked NYT article in the reply-to was https://www.nytimes.com/2025/01/22/world/americas/mexico-car... (archived: https://archive.ph/6Sn0Y), which doesn't mention Slim at all.