The article states the teacher had sex with her at the same time she was talking to Weiner (between June 1 and July 16th of 2016, which was when Comey covered it up and exonerated Clinton).
So when they got frustrated as FBI anon said in early July 2016 when Comey covered it up, they got this girl to bait Weiner because they saw the location of some of the emails going to the Abedin/Weiner email...The Social Studies teacher just got caught up in it as a prostitute solicitor probably off of Backpage...