A survivor of last week's school shooting in Florida has denied claims he is an actor with an anti-gun agenda.
Speaking on CNN, student David Hogg said he was a witness.
Conspiracy theorists online have accused the survivors of the shooting at Marjory Stoneman Douglas High of being paid actors who travel between the sites of mass shootings.
An aide to a Republican state representative has been fired for repeating the unsubstantiated claims.
David Hogg denounced the allegations on Tuesday night.
"I'm not a crisis actor," David said in an interview with CNN's Anderson Cooper.
"I'm someone who had to witness this and live through this and I continue to be having to do that."
"I'm not acting on anybody's behalf."
What are the claims?
Conspiracy theorists' unsubstantiated claims online are that some of the Florida shooting survivors are actually paid actors, who travel between sites of mass shootings to push an anti-gun agenda.
Similar theories circulated on social media after the Las Vegas shooting in October, the worst in modern US history.
An aide to a Florida state representative, Benjamin Kelly, sent an email to the Tampa Bay Times repeating those online claims about David Hogg and his fellow students.
Florida representative Shawn Harrison, whom Mr Kelly worked for, fired his former aide on Tuesday night and denounced his behaviour in a tweet.
Tonight Mr. Kelly was terminated from his position as my District Secretary. I am appalled at and strongly denounce his comments about the Parkland students. I am again sorry for any pain this has caused the grieving families of this tragedy.— Shawn Harrison (@Shawnfor63) February 21, 2018
Florida senator Marco Rubio also denounced the claims made against David and his fellow students, calling those who made them "disgusting idiots".
Claiming some of the students on tv after #Parkland are actors is the work of a disgusting group of idiots with no sense of decency— Marco Rubio (@marcorubio) February 20, 2018
Some theorists online even suggested David Hogg cannot be trusted because his father used to work for the FBI.
One post on Twitter had the headline "Outspoken Trump-Hating School Shooting Survivor is Son of FBI Agent; MSM Helps Prop Up Incompetent Bureau", linking to a video in which David spoke in favour of tighter gun control.
Son of the US president Donald Trump Jr. was criticised for liking the tweet.
President Trump meanwhile signed an order to ban "bump stocks", modifications on guns that increase the firing rate.
What did David Hogg say?
David Hogg and his fellow classmates have called for tighter gun control laws in the wake of the shooting, which left 17 of their teachers and fellow students dead.
In the interview, David denied wanting to repeal the second amendment, which allows Americans the right to bear arms.
He stated that Americans should have the right to own weapons, provided they are "not going to go out and commit these atrocities".
"We have a right to live just as we have a right to bear arms," he said.
David, a student journalist, interviewed his classmates as they hid from the Florida shooter.