On 28 August 1996, South African police officers in Pretoria observed a bright object and pursued it in a helicopter.

Pretoria matters because it is a police helicopter pursuit with official reports.
Documented
Police officers observed a bright object
Documented
The officers pursued it in a helicopter
Debated
The identity of the object
Unverified
Extraterrestrial origin
Sources are kept in separate layers: official and contemporary material is documented; secondary UFO literature is treated as debated, not as primary evidence.
Documented source.
Secondary / debated material.