Sen. Marco Rubio (R-FL) sent a letter to Twitter CEO Jack Dorsey today demanding to know why the platform has failed to prevent the spread of Chinese communist propaganda across the service.

The Florida senator highlighted a doctored image spread by Zhao Lijian, a senior official in China’s propaganda arm, the information department. The doctored photo depicts an Australian soldier holding a knife to the throat of an Afghan child.

The tweet, posted on Nov 29, has accumulated nearly 15,000 retweets so far. It has not been taken down by Twitter, nor has Twitter applied any label to the image informing users that the picture has been manipulated.

“It defies belief that Twitter is unaware of this image, which falsely portrays an Australian soldier holding a bloody knife to the throat of a young, Afghan child, as Australia’s Prime Minister Scott Morrison requested the image be taken down,” wrote Rubio.

The letter asks Twitter to answer several questions, including whether it has conducted a review of the tweet from Lijian, and if so, why no action has been taken as a result.

Rubio argued that Twitter has a “right as a private company,” to censor its services, but that its use of this right raises the question of whether Twitter deserves special legal protections under Section 230 of the communications decency act, a law that is critical to the business model of online platforms.

The Florida senator has previously argued it is “positive” that social media companies police “hate speech” from their users. He has never retracted or publicly reconsidered this statement. Rubio will face a Republican primary election in 2022.

Allum Bokhari is the senior technology correspondent at Breitbart News. His new book, #DELETED: Big Tech’s Battle to Erase the Trump Movement and Steal The Election, which contains exclusive interviews with sources inside Google, Facebook, and other tech companies, is currently available for purchase.