Forensic analysis has revealed that three of the terrorists who were responsible for the death of four Saudi policemen this week in a border post attack had served time behind bars.

“The DNA fingerprints of these men matched those of suspects wanted by security authorities,” said Maj. Gen. Mansour Al-Turki, Interior Ministry spokesman.

Mousa Al-Shahri, one of the terrorists, had been sentenced for terrorist activity and was released in 2012, while Saleh Al-Omari had also been arrested for terrorism-related charges and released in 2011.

Ayoub Al-Suwaid, another attacker, had been reported missing and Faraj Al-Saiari had served time for drug abuse. His parents had told authorities that he had left the Kingdom abruptly and had traveled to areas of unrest.

Abdulaziz Al-Rashoudi had been repatriated from conflict zones and was released in 2012.

The men had opened fire at security forces on Friday after approaching the border post in a jeep, while another security patrol vehicle had been seized by two of the men, who had ambushed a government building and blew themselves up on Saturday. Three had been killed in a high-speed car chase and one arrested.