Organisers of a pioneering drama project in a Palestinian refugee camp have accused Israel of a campaign of intimidation after soldiers arrested a third member in the space of a few days.

Rami Hwayel, an actor with the Jenin Freedom Theatre, was arrested two days ago at an Israeli checkpoint in the West Bank as he drove home with friends to see his family for Ramadan.

The arrest is the latest in a series of blows to the theatre, which was left reeling after the murder in April of its charismatic founding director, Juliano Mer-Khamis, the son of an Israeli mother and a Palestinian father. His murder has not been solved.

Colleagues said they were bewildered by the arrest, describing Mr Hwayel, who was to perform in an upcoming production of Samuel Beckett's Waiting for Godot, as "dedicated to his work". Israel has given no explanation for his detention.

Just 10 days previously, Israeli troops had stormed the theatre, located in one of the occupied West Bank's most battle-scarred towns, arresting Adnan Naghnaghiye, the theatre's location manager and Bilal Saadi, a board member.

Those involved with the project have been left guessing at the motives behind the spate of arrests. Lawyers and family members have not been allowed to meet with the detainees, the army referring only to "security" concerns in the cases of the first two arrests. "We're in the dark. We don't know why these arrests are happening – we don't know why we are being targeted. We're a cultural organisation fighting for freedom," said Jacob Gough, the theatre's acting managing director.

Some speculate that the arrests may be connected to the activities of Dror Feiler, a co-founder of the theatre, and one of several arrested and deported last month for attempting to breach Israel's naval blockade of Gaza.

Israel has been particularly sensitive to perceived challenges to its sovereignty by activists in recent months. It is still smarting from international criticism of its storming of a Gaza-bound aid convoy last year that left nine activists dead.

Meanwhile, the theatre's work has provoked strong reactions from Palestinians, some of whom object to its liberal values, such as its sometime anti-authority message, and by encouraging men and women to work closely together.

Mr Khamis, who founded the theatre in 2006, was shot dead outside the venue in early April by a masked gunman.