Brennan Leach, a 15-year-old who asked Hillary Clinton a question during a Town Hall event in Haverford, Pennsylvania, once played a small part in a short film.
There's no evidence that Brennan was "hired" by the Clinton campaign and "planted" in the audience with a specific question to ask during the Town Hall event.
On 5 October 2016, a video published to YouTube advanced the conspiracy theory that Hillary Clinton had been "caught" using a hired child actor who was "planted" in the audience of a Town Hall campaign event in Haverford, Pennsylvania, to lead off by asking the candidate a pointedly anti-Trump question:
Hillary has no shame; she used a 15 year old child actor (Brennan Leach) to further her anti-Trump narrative. What kind of role model is Hillary for women teaching teenage girls that cheating is an acceptable form of winning?
This video was picked up by several web sites known for promulgating conspiracy theories, such as Info Wars and Zero Hedge:
At a Hillary Clinton town hall yesterday in Haverford, Pennsylvania, a 15 year old girl was supposedly "chosen at random" to ask a question of the former Secretary of State. But, the well-scripted performance raised some suspicion with a YouTuber named Spanglevision who decided to dig a little deeper. And, wouldn't you know it, the "random" participant was none other than child actor, Brennan Leach, whose father just happens to be Pennsylvania democratic State Senator Daylin Leach. Oh, and in case it wasn't obvious, Daylin supports Hillary for president ... shocking.
Here is the full analysis from Spanglevision. Among other things, he points out that Brennan is the only participant of the night who reads her question from a prepared script.
As is common with most conspiracy theories, the narrative was based on a few realities. Brennan Leach is — or at least was — a child actress (if having a small part in a single short film qualifies one as a "child actress"), she is the daughter of Pennsylvania state senator Daylin Leach, and she appears to have been the only audience member called upon who read her question from a piece of paper.
While these three facts were presented as "evidence" that Clinton was "caught" using a child actress to ask a pre-arranged question, that conclusion was based on nothing more than speculation
It's certainly likely that young Brennan Leach's political views have been informed by her parents, it's possible she received a prominent seat at the town hall event (making her more visible and more likely to be chosen for a question) because of her father's political prominence in the state, and it's not unreasonable to assume that her father talked to her before the event (and possibly even suggested a question for her to ask).
But if the Clinton campaign had truly cast about for a "child actor" to ask a pre-arranged anti-Trump question, they likely would have hired one with a stronger résumé than a single bit part in a short film, selected an actor who could recite a question without having to read it from a "script," and coached their choice not to offer her real full name (thereby subjecting the whole plot to exposure by anyone familiar with the Internet Movie Database).
In short, the only aspect of this claim that suggests a conspiracy is the counterintuitive assertion that it was so easy to uncover.
Steve Hoenstine, Senator Leach's Director of Communications, denied that Brennan was a paid actor, calling the attacks against the 15-year-old "disgusting":
She wrote the question, got to ask it to Hillary Clinton and she answered it. It was a great moment for her. And since then this 15 year-old girl has been the subject of vile attacks, thousands of them. It’s disgusting.