The Palestinians who were arrested shortly after the attack, Youssef Kamil, 20, and Mohamad Abu al-Roub, from the town of Qabatiya located in the Jenin Governorate in the northern West Bank, entered Israel illegally where they remained and worked for around two weeks.
During their investigation by the Shin Bet, it emerged that the two decided to carry out a stabbing attack and murder Jews in revenge for the death of a friend, Ahmed Abu al-Roub, who was killed during an attempted stabbing attack at the Jalameh Crossing.
The two were also said to have been motivated by violent events occurring at the al-Aqsa mosque in recent months.
According to the investigation, the Shin Bet discovered that one of the terrorists had planned prior to his entry into Israel to carry out a stabbing attack against Jews. Conspiring together, the two purchased a knife and planned their attack, which included an escape route after the bloodletting.
Confessing their involvement, the two reconstructed how the murder was committed, telling investigators they had used a knife, a pickax and a fan.
The version of events corresponded with the findings at the scene, with all of the stated objects being stained with Shmerling's blood.
Additionally, DNA of one of the defendants was also found on the switch handle of the pickax.
Footage from the security cameras inside the business premises also shows one of the terrorists walking with Shmerling to a vehicle to load a battery. Afterwards, the second terrorists is seen leading him into the room in which he was slain.
Underpinning suspicions of nationalist motivations were the post uploaded on Facebook by the two several days prior to the attack.
On October 4, Shmerling arrived at the warehouse where the attack took place and knocked on the door. When the terrorists opened it to let him in, they were reprimanded for only being “good at sleeping and eating.”
Against a background of disputes, the two had already resolved that Shmerling would be their victim. Kamil was asked by Shmerling to load a forklift battery onto his vehicle. After doing so, Kamil returned to the room when the two decided to carry out the attack.
According to the plan detailed in the indictment, the two culprits agreed that Abu al-Roub would lead Shmerling into the room pretending that the fridge was broken and distract him while Kamil would stab him with the 18-inch knife they had purchased and hid in a mattress.
While Shmerling was checking the fridge, Abu al-Roub made small talk to distract him from the impending attack. Shortly after 10:30am, Kamil pulled out the knife from the mattress and shabbed Shmerling behind his left shoulder.
In an attempt to defend himself, Shmerling picked up a chair in the room and hit Kamil with it in the leg. Abu al-Roub then pushed Shmerling and beat him around the head with a fan nearby while Kamil continued to stab him repeatedly in his stomach, chest and elsewhere.
Abu al-Roub then left the room and returned shortly after with a pickax by the door and stuck Shmerling with it in the stomach.
The indictment highlights that due to the knife bending in the process of the attack, Kamil threw it on the floor and took the pickax from al-Roub and used it to strike Shmerling in the head.
Abu al-Roub then entered the shower room where he changed his clothes while Kamil photographed Shmerling on his cellphone before he also took a shower and changed his clothes. Afterwards, the two left Shmerling lying in a pool of blood and fled the scene.
In an effort to conceal their crimes and destroy the evidence, the two terrorists smashed their phones and threw them away.
Circumstances behind the incident were not immediately clear, with investigators originally suspecting that 70-year-old Shmerling from Elkana, who was found in a coal storehouse belonging to his family in Kafr Qasim industrial zone with signs of severe violence on his body, was murdered following a dispute involving money.
Days later, investigators began to suspect that national motivations had led to the murder.