(This version of the story corrects fifth paragraph of Monday's story to say witness Moumouni Karimou is from Niger, not Nigeria)
By Nate Raymond
NEW YORK (Reuters) - An African security guard on Monday told a U.S. judge that he saw an American diplomat shot to death in Niger 14 years ago, and identified the shooter as the suspect who has been indicted for the crime.
Moumouni Karimou told a federal judge in Brooklyn, New York, he had smoked with the shooter just minutes before he witnessed the fatal carjacking.
Prosecutors called Karmou to testify about the murder of U.S. Department of Defense official William Bultemeier in 2000.
They have charged Alhassane Ould Mohamed, a Malian national, in connection with the shooting of Bultemeier and Marine Corps Staff Sergeant Christopher McNeely, who survived the attack.
Karimou, a security guard from Niger working that night at an Air Afrique building, said he identified Mohamed as the shooter from photos and mug shots showed to him by agents from the U.S. Federal Bureau of Investigation.
But Karimou said he initially did not tell the agents everything he knew about the shooting, including that he had spoken with the shooter.
"I was afraid I might get killed," he said through a French language interpreter. "I was scared."
He testified at a hearing prompted by efforts by Mohamed's lawyers to suppress eyewitness identifications of their client as unduly suggestive or unreliable.
Mohamed, 45, was indicted in 2013 for the murder of Bultemeier and attempted murder of McNeely as they left a restaurant in Niamey, Niger on Dec. 23, 2000.
Prosecutors said Mohamed and another assailant, armed with a pistol and AK-47 assault rifle, demanded Bultemeier hand over the keys to his sport utility vehicle, which bore U.S. diplomatic plates.
Mohamed then shot Bultemeier, prosecutors said. McNeely tried to help Bultemeier when Mohamed's accomplice shot both men, prosecutors said.
Mohamed and his accomplice then fled in the car, prosecutors said.
Mohamed was arrested by Malian police but escaped from custody in May 2002, prosecutors said.
He was arrested in Mali again in 2010 in connection with an attack on a convoy of Saudi Arabian officials in Niger that left four dead.
Sentenced in Niger to 20 years in prison, Mohamed escaped again in June 2013 with other inmates who launched an assault coordinated by Boko Haram, prosecutors say.
Mohamed also had connections to militant groups including the National Movement for the Liberation of Azawad and al Qaeda in the Islamic Maghreb, prosecutors said.
He remained at large until French forces in Northern Mali apprehended him in November 2013. He was extradited in March 2014 to the United States.
Reporting by Nate Raymond in New York; Editing by David Gregorio