Complex sentence: In 1974, he went to what was now the Democratic Republic of the Congo; the government of Mobutu Sese Seko contracted him as an investigator and he took part in technical assistance with small rural producers.
Split into simpler sentences: In 1974, he went to what was (now the Democratic Republic of the Congo). The government of Mobutu Sese Seko contracted him as an investigator and he took part in technical assistance with small rural producers.