Technology workers in Kenya have held a vigil for a colleague who died in unclear circumstances after she was unable to travel to her home in Nigeria for two years

In a drab office in Kaduna, the capital of Nigeria's north-central state of the same name, Ladi Anzaki sat pensively at her desk.She had just returned to the office after a short lunch break.It had been a busy Tuesday and she had spent most of her time talking to various clients and customers.