Their comments came just after another man authorities have linked to the plot was released on bail Wednesday in Kenya. Kenyan authorities had arrested Salmin Mohammed Khamis, 34 years old, on suspicion of harboring participants in the plot—including Mr. Luyima—in his home in the coastal town of Mombasa before the attack.
Mr. Khamis was arrested in 2003 on suspicion of involvement in a plot to bomb an Israeli airliner in Mombasa and a hotel. He was later acquitted, but at the time, he gave a statement to Kenyan authorities that he was affiliated with al Qaeda and was plotting to bomb the U.S. Embassy in Nairobi. So far, authorities say he hasn't been implicated further in the Kampala attacks.
Al Shabaab had initially tapped an al Qaeda-trained fighter named Muhamoud Mugisha to carry out the Kampala bombings, said Mr. Mugira.