The US State Department has said diplomatic security and FBI agents will be sent to Sudan to investigate the murder of a US diplomat and his driver.
Mr Granville was shot five times while travelling in his car
John Granville, who worked for the US Agency for International Development, died when shots were fired at his car in Khartoum.
Sudan's foreign ministry condemned the killings and ruled out terrorism.
A State Department spokesman said US investigators were in the process of obtaining visas for Khartoum.
"They will... work closely with the Sudanese government to determine who is responsible for these murders and bring them to justice," spokesman Sean McCormack said.
The Sudanese government has agreed to admit the team.
Mr Granville, 33, died of his wounds after his car was shot at during the early hours of Tuesday, as he made his way home from a New Year's Eve party.
His driver, 40-year-old Abdel Rahman Abbas, was killed instantly.
Sudan's interior ministry said Mr Granville's embassy vehicle was fired on by gunmen in another car as it drove through a residential area of western Khartoum.
It said Mr Granville was shot five times in the hand, shoulder and stomach.
"On behalf of the Sudanese Foreign Ministry, we would like to express our deep regret and our condemnation of this incident," foreign ministry adviser Ali al-Sadiq told the BBC.
"We don't believe this incident has any relation whatsoever to any act of terrorism," he said.
However, a spokesman for the US embassy in Khartoum said it was "too early to tell" whether the attack was related to terrorism.
The shooting happened the day after a joint African Union-United Nations force took over peacekeeping duties in Sudan's war-torn Darfur region.
Anti-Western and anti-US feelings are running high in Sudan, because of Western criticism of Khartoum's policies in Darfur, correspondents say.
But attacks on foreigners in Khartoum have been rare.