Focus Features is developing British director Daniel Mulloy's feature directorial debut project A Cold Day, about a trainee teaching assistant's relationship with her class teacher and a vulnerable special needs student. Set in a tough New York high school, the story charts the fall-out after a violent incident triggers a psychological breakdown in the assistant and events spiral out of control.

"A malicious student, early on in the film commits an offence that has huge repercussions which affect all of those involved and beyond," Mulloy, 34, said. "Misunderstandings and rumour swell to a point that lives are put in danger… all are forced to face their fears, both inner and outer. In a place where words can kill, the truth can be more dangerous hidden than embraced."

Focus confirmed the project was in development but was not at the greenlight stage. That said, the filmmaker is clear about whom he would like to star in A Cold Day.

For the lead role as the assistant Mulloy favours Arta Dobroshi, the Kosovar actress who starred in the Dardenne brothers' 2008 Palme d'Or contender Lorna's Silence. Mulloy and Dobroshi just wrapped a short film in Kosova's capital Prishtina through their production company Flutra Films and were at the Paris Project co-production forum to present a separate project.

Mulloy is eyeing Melissa Leo for the role of the class teacher and said he and Dobroshimet the Oscar winner over lunch and were "thrilled by her enthusiasm in embracing the project."

Mulloy has won more than 80 awards for his shorts such as Bafta winner Antonio's Breakfast, which premiered at Sundance Film Festival in 2006. Baby, which starsDobroshi, was named best British short at Edinburgh in 2010 and screened atSundance earlier this year.

An Arta Doboshi poster can be seen on the streets of Paris as momentum builds in France for her new Kosova set feature film with Mulloy. The film, still in development, is part of the ongoing Paris Projects initiative.