What I find cringeworthy is @Suhail saying they thought he was in the US but actually was in India—outing his company as not checking employment eligibility [0]. If he was actually allowed to work in the US—which doesn't seem to be the case since he hasn't responded to any replies asking about this—then they hired someone who underperformed, or in the worst case violated a company policy they might have that employees cannot have another job. Hardly seems like something worth shouting from rooftops.
The Tweet clearly says they fired in him the first week and confronted him about the lying/scamming. It seems very clear that they figured it out right away and confronted him about it.
But they haven't checked his employment eligibility or he wouldn't have started his first week.
Legally, you have three days to complete an I-9 after starting a new position.
Given that there's no oversight of the verification process, that can slide, too.