Laode Ardina Laude Rasila, 35, arrived in chains at around 10.30am and walked officers to a row of car repair shops here along Jalan Subang Persiaran Penaga.
He later pointed to a drain. Police officers found the pump gun he had thrown away when he was escaping from the AmBank branch he robbed on Oct 23.
He was later taken back to the Subang Jaya police headquarters.
Subang Jaya OCPD ACP Yahaya Ramli police retrieved the weapon at around 11am.
A two-hour forensics investigation began soon after while police swept the rest of the area for other evidence.
According to a police source, the pump gun still had four rounds of ammunition in it, but he declined to say how many shots had been discharged.
The security guard, who was caught trying to flee the country in Johor on Sunday, allegedly shot dead bank officer Norazita Abu Talib, 37, before running off with RM450, 000 from the bank's vault.
It was revealed that his MyKad was fake.
