A dozen masked men shot five Christians to death as they came out of their church building in Sukkur, Pakistan, on July 15, two months after a banned Islamic extremist group sent church leaders a threatening letter, reports Compassion News Direct.

According to CDN, Pastor Aaron John and church members Rohail Bhatti, Salman John, Abid Gill and Shamin Mall of the Full Gospel Church were leaving the church building after meeting to discuss security in light of threats they had received, said the pastor's son, Shahid John.

"As we came out of the church, a group of a dozen armed gunmen came and opened fire at us," said Shahid John, who survived a bullet in his arm. Besides Shahid John, five others were wounded in the attack.

Kiran Rohail, widow of Rohail BhattiI, said church leaders had received a letter from Islamic extremist group Sip-e-Sahaba (formerly Sipah-e-Sahaba until it was banned) warning the Christians to leave the area.

According to CDN, the Sip-e-Sahaba and Sunni Tehrik extremist groups are both linked with an area madrassa (Islamic school). Their students had reportedly been threatening the church since 2008, Christian sources said.

Sources told CDN that the masked gunmen involved in the July 15 shooting had young physiques like those of students and that the manner of their attack gave the impression of trained extremists.

Sources believe that the madrassa students that have threatened the church since 2008 belong to the Sunni Tehrik extremist group.

Although pastor John and Bhatti had reported the threats, relatives say officers at the local station did not take them seriously and refused to register a First Information Report (FIR).

According to CDN, the shooting was confirmed by an independent government source who added that the media had not reported it because of pressure from local Muslims.