A Canadian police officer interviewed in a documentary says:
"Both (guardians) on Saturday and Sunday believed that Jonathan was with the other guardian. On Sunday evening the two of them met at some location in La Ronge and identified that, you know, mom's saying to grandma "You don't have Jonathan?" and vise versa. At that point in time they became concerned because neither of them had seen Jonathan for the previous day."
The preposition "for" strikes me as unnatural. I would have used either "on" or "in". My understanding is that the definition of "for" invoked here is lasting, an indication of duration of time, as in "I was digging holes for the entire day."
However, for the previous day doesn't sound idiomatic at all. Google Books hits all point to other usages of "for", e.g. "Let's pay for the previous day". People don't say "I did that for yesterday," but rather "I did that for the entire day yesterday." By the same token, "I kept hearing about the event for the entire year last year" instead of "I kept hearing about the event for last year." Is "for the previous day" idiomatic?
Also which preposition would best replace "for" here? Since this line talks about a length of time, "on" sounds better to me.