A black political activist died in an East London hospital shortly after he was arrested and jailed by police, officials said yesterday. The cause of death was not disclosed.

Mbuyiselo Mbotya, 35, was arrested Friday night on an unspecified criminal offense, said a police spokeswoman quoted by United Press International. He was taken to the police station in King Williamstown, about 40 miles west of East London, "where he became ill," she said.

Mbotya, who lived in Ginsberg, a black township near King Williamstown, was the third resident of the suburb to die in police custody in the past six weeks. Since the death of black leader Steve Biko in September 1977, at least 27 people have died in police custody.

Mbotya's sister, Nomtandazo, said her brother was a member of the United Democratic Front, the largest legal black opposition group in the country, with about 1.5 million members.

In other developments, police using whips and truncheons scattered peaceful blacks at funerals east of Johannesburg, and security forces fired tear gas at students outside Cape Town after an address by a white antiapartheid activist, witnesses said.

Blacks at the funerals also claimed that police masqueraded as foreign journalists and tried to film mourners.