Mogadishu pastor Ali Hussein Weheliye was killed in the attack in October, but reports of the incident didn't come out until this week.
Experts at the missions think-tank the Joshua Project estimate Somalia is 99 percent Muslim.
International Christian Concern's Jonathan Racho agrees with that statistic and says the overwhelming numbers make it difficult to be a Christian in Somalia.
"A vast majority of Somalis are Muslims, but there are hundreds of Christians in Somalia. This pastor was the pastor of an underground church," Racho said.
"Christians in Somalia have to go underground and they don't give away their identities because once al-Shabaab knows someone is a Christian, that is a death sentence for that person," he said.
Racho makes the death sentence claim because al-Shabaab is a jihadist militia with close ties to Osama bin Laden and the al-Qaida terrorist group.
Intelligence sources say most al-Shabaab fighters receive training at al-Qaida or Taliban training camps in Pakistan before being sent to Somalia for the declared anti-Christian jihad in that eastern African nation.
Racho said these facts are evidence Weheliye’s murder is not an isolated incident.
"Al-Shabaab has gone on a campaign of killing Christians. One of its official policies is to eradicate Christians from Somalia," Racho said.
"This year alone, Pastor Ali is the fifteenth Christian to be killed in Somalia. The killing has been going on for the past several years. The church in Somalia is going through a difficult time. If this trend continues many more Christians will be killed and many will be forced to leave Somalia," Racho explained.
The American Enterprise Institute's Michael Rubin agrees with the assessment.