KARACHI, Pakistan, Aug. 20 —A leading constitutional lawyer was named by the Pakistani Government today to defend Sheik Mujibur Rahman, the imprisoned Bengali leader currently on trial for treason.

The Pakistani radio announced tonight that the Government had prevailed upon A. K. Brohi to act as lawyer for Sheik Mujib, who is charged with “waging war against Pakistan,” and that Mr. Brohi left Karachi tonight for Rawalpindi for his first meeting with his client. The broadcast did not say whether the trial was being conducted in Rawalpindi.

Tonight's announcement was the first one since the martial law administrator announced two weeks ago that Sheik Mujib would go on trial Aug. 11, although earlier this week Government spokesman confirmed that the trial had begun. The trial is being held in secret and its place has not been disclosed.

The Pakistani radio said that the Government had asked Sheik Mujib to name any defense lawyer he wanted and that he had presented a list of three names, the first of which was Mr. Brohi's. Mr. Brohi at first said he was unwilling to serve because of the pressure of a heavy legal practice, the radio said, but finally agreed to undertake the defense.

Sheik Mujib was arrested by East Pakistani soldiers at his home in Dacca, the capital of East Pakistan, March 26, and has not been seen since by any foreigner or politician. It is generally believed that he will be given the death sentence.

In Pakistan's first general election, Dec. 7, Sheik Mujib's party, the Awami League, won 167 seats in the new 313seat National Assembly, which was to draft a constitution to return the country to civilian rule, and he presumably would have been named Prime Minister. Pakistan has never had a popularly elected government since she became independent of Britain, along with India, in 1947.

The National Assembly was never convened by Pakistan's President, Gen. Agha Mohammad Yahya Khan, and against a background of mounting unrest in East Pakistan the army began occupying the province on March 25 and undertook to crush the provincial separatist movement, with heavy loss of lives.

The occupation followed breakdown of talks between General Yahya and Sheik Mujib, who had sought a large measure of autonomy for East Pakistan, which is separated from the West by 1,000 miles of Indian territory.

In another development, East Pakistan's Governor, Lieu. Gen. Tikka Khan, announced criminal charges against 13 more members of the now‐outlawed Awami League members elected to the National Assembly. This brought to 72 the number now charged with sedition, murder, rape and other crimes.