The investigation into last year’s nearly fatal attack on Salman Rushdie has expanded to explore potential international involvement, according to a US district attorney.

Jason Schmidt, the US district attorney overseeing the case, revealed a separate inquiry led by the US federal government, specifically the US Attorney's Office into the case of Hadi Matar with a focus on Iran. Matar, a 25-year-old man accused of stabbing Rushdie multiple times during the writer’s appearance at a summer cultural festival last August is now accused of having possible connections to foreign entities.

“There are some areas that we have to sort of confine ourselves to the four corners of the charges that we've asserted, which is essentially an attempted murder in the second-degree charge. That's our top count,” said Schmidt.

This scrutiny is linked to Iran's historical involvement due to Ayatollah Khomeini's 1989 fatwa against Rushdie because of what he asserted were sacrilegious sections regarding Islam in Rushdie's novel, "The Satanic Verses."

Iranian religious groups have also offered rewards for Rushdie, with such offers extending as recently as last year.

While Matar's assault on Rushdie was initially seen as an individual act, concerns have arisen regarding foreign support, especially given Matar's time in Lebanon and his possession of a counterfeit Hezbollah-related ID.

The investigation's complexity extends beyond local jurisdiction, involving national security and diplomacy amid ongoing negotiations with Iran.

Experts suggest that Matar was possibly influenced by Hezbollah during his time in Lebanon and that this may have played a role in his alleged attack. Iran has denied direct involvement but expressed support for the attack.

The focus of the investigation remains on Matar, with the US State Department imposing sanctions on an Iranian organization linked to bounties on Rushdie.

Tensions between the US and Iran have escalated in recent years, marked by events such as the assassination of General Qasem Soleimani and alleged plots against US officials.