Ahliya University professor Farouk Kadouda, a prominent critic of the Sudanese government, returned home on October 31 to find his teenage daughter beaten unconscious with a warning note for him by her body.
In a letter to president Omar al-Bashir on behalf of Human Rights Watch academic freedom committee, Jonathan Fanton, former president of the New School University in New York, demanded an impartial inquiry into the incident and alleged police indifference. "Dr Kadouda's experience will have a deleterious and chilling effect on the exercise by other citizens of their fundamental right to seek information and freedom of expression," he wrote.
Dr Kadouda believes the assailant was a member of a militia affiliated to the ruling National Islamic Front. But Peter Woodward, professor of politics at the University of Reading, said: "It is very difficult to know whether such acts are encouraged or condoned by the government, but I know of dissidents who have spoken of attacks of this order.
"There is a climate of inconsistent repression. On occasions the government seems to allow things to go by, particularly press criticism. At other times it seems to want to intimidate the opposition."
Parties have been banned since 1989 but earlier this year the government tried to create a controlled multi-party system. The main opposition, the National Democratic Alliance, of which Dr Kadouda's Sudanese Communist Party is a part, has boycotted the process.
Professor Woodward said: "The government is trying to play for time and to split the NDA." President al-Bashir has met leaders of the Umma Party, which is part of the Eritrea-based NDA, and has been making concessions including the return of confiscated property. But the Communist Party has remained aloof and leading figures such as Dr Kadouda have maintained their open criticism.
Joseph Saunders, who heads the academic freedom project at HRW, said: "The evidence we have strongly suggests that the attack ... was part of a politically motivated campaign of intimidation."