Complex sentence: He was one of the UN inspectors who examined the use of chemical weapons in Iraq in the 1990s and he returned to the country in 2002 to examine whether the regime restored the banned weapons program, for which they found no evidence.
Split into simpler sentences: He was one of the UN inspectors who examined the use of chemical weapons in Iraq in the 1990s. He he returned to the country in 2002 to examine whether the regime restored the banned weapons program, for which they found no evidence.