A member of the team investigating an attack on the U.S. Embassy in Yemen was killed Thursday, Yemeni officials said.
The Yemeni national, a security official at the embassy, was shot dead on his way to work, Interior Ministry officials said.
A senior U.S. State Department official confirmed that the embassy employee was killed while off duty.
The killing of Qassem Aqlan shows the hallmarks of al Qaeda, the officials said. Al Qaeda in the Arabian Peninsula (AQAP) has been blamed for numerous attacks in Yemen.
Gunmen on a motorcycle shot at the vehicle Aqlan was in. He died at the scene, the Interior Ministry officials said.
"Motorcycle attacks are currently al Qaeda's main tactic," a senior Interior Ministry official said, adding that such attacks "are easier for terrorists to coordinate and plan for."
The shooting took place along Siteen, a main street in the Yemeni capital of Sanaa, which is generally considered one of the safest, officials said. The Yemeni president's house is on the same road.
Aqlan worked at the embassy for nearly two decades, Interior Ministry officials said.
While some Interior Ministry officials at first said Aqlan was overseeing the investigation into last month's attack on the embassy, others later told CNN he was not.
Interior Minister Abdulkader Qahtan is overseeing that investigation, said a Yemeni government official not authorized to speak to the media.
Aqlan's death "sends a message that if you're working with the Americans you'll be targeted no matter who you are," the official said.
Hundreds of demonstrators gathered in front of the embassy in September to protest the video "Innocence of Muslims," which maligns the Prophet Mohammed. The demonstration turned violent, and some protesters broke into the embassy.
Clashes between security forces and demonstrators left at least four protesters dead and more than 30 people injured.