Sony Pictures’ hopes of countering Netflix and Amazon in the increasingly popular market for the Japanese-style animated videos known as anime has hit a snag. The U.S. Justice Department has extended its antitrust review of Sony’s proposed $1.2 billion acquisition of anime-streaming service Crunchyroll from AT&T’s WarnerMedia, according to three people familiar with the process.

The probe, which could delay the sale by several months and potentially kill it, seeks to determine if the deal would give Sony dominance in the anime-streaming market, these people said. Sony in recent years has acquired a number of anime distributors and streaming services, including Funimation, Crunchyroll’s main U.S. rival. Meanwhile, viewer demand for anime has surged during the pandemic. Netflix has been expanding its anime offerings as well.

While anime is a relatively niche market—Crunchyroll had 4 million subscribers in February, a fraction of the numbers for mass-market streaming services like Netflix and Disney+—Sony doesn’t own any streaming services in the U.S. other than Funimation. That sets it apart from other major TV and film studios, most of which are now allied with streaming services. For that reason, the deal is strategically important for the Japanese electronics and entertainment giant.