Susanna Liew Sow Yoke, the wife of Koh, told the inquiry, held by the Human Rights Commission of Malaysia (Suhakam), that the police thought the plate numbers were fake.
The inquiry entered the second day today with Liew as the second witness.
Koh, 62, was abducted from his car by a group of more than 10 men in a convoy of vehicles at Jalan Persiaran Tropicana in Petaling Jaya on Feb 13.
CCTV footage showed at least three black SUVs were involved in the abduction.
There was speculation the abduction might have been connected to his alleged attempts to proselytise Christianity, but this claim was dismissed by his family.
The Suhakam inquiry will also consider whether Koh’s disappearance and three other missing persons — Amri Che Mat, Pastor Joshua Hilmy and his wife Ruth — were cases of enforced or involuntary disappearances as defined under the International Convention for the Protection of All Persons from Enforced Disappearance.
Social activist Amri, 44, who co-founded charity organisation Perlis Hope, has been missing since Nov 24 last year.
His wife, Norhayati Ariffin, had said witnesses saw five vehicles blocking the path of Amri’s car before he was taken away just 550 metres from their home in Bukit Chabang, Perlis.
Joshua and his wife Ruth, meanwhile, were last seen on Nov 30 last year.
Liew said the police had on March 6 asked her to meet SAC Fadzil Ahmad and other officers at the Petaling Jaya police headquarters.
“At 3.45pm I met SAC Fadzil in a meeting room where he told me the police had no significant leads in the case,” she said.
She was then told the police had collected some pictures from a CCTV camera mounted on an advertisement board near the scene of the abduction.
“I was shown photos of three vehicles: Raymond’s Honda Accord (ST5515D), a black pick-up truck (number plate starting with WC) and a Toyota Unser (number plate starting with BKB).
“The number plates were very clear and when I asked if the numbers had been traced, Fadzil said there were no such numbers in the car registration records, implying that they were fake,” she said.
The date on which the pictures were taken were also not obtained, she added.