In 1964, then President of Iraq Abdul Salam Arif appointed then Staff Major Al-Naif as Deputy Director Military Intelligence.

He held regular secret meetings with Barzani and was instrumental in bringing the First Iraqi-Kurdish War to a peaceful end.

In 1969, Al-Naif secretly returned to Northern Iraq and was welcomed back and protected by the Barzani, and also by the Iraqi troops that were sent to fight the Kurdish militants.

It is unknown why he decided to leave Northern Iraq, but he maintained close relationships with the Kurdish leaders and Iraqi opposition to the Ba’ath Party.

There are reports that he became concerned that his anti Ba’ath coalition movement was infiltrated by Saddam Hussein's secret Mukhabarat apparatus and he was informed of attempts to assassinate him in Northern Iraq by them.

Al-Naif enjoyed a good relationship with the Shah of Iran Mohammed Reza Pahlavi, Jordan's King Hussein and Saudi Arabia's King Faisal bin Abdul Aziz, who supported his opposition to Saddam Hussein's Ba’ath Party Government in Iraq.

He was critically injured from multiple gunshot wounds as he left the Intercontinental Hotel in London's Park Lane and died the following day.

The assassins were named as Salem Ahmed Hassan, a Palestinian belonging to the Abu Nidal terrorist group, who was charged and sentenced to life in prison in 1979,[2] and Sadoun Shakir, the head of the Iraqi Intelligence Service, who entered Britain under a false name using an Iraqi diplomatic passport.