The former Inspector-General of Police was agreeing to points raised on Monday (Oct 30) by lawyer Gurdial Singh who is representing Koh's family at a public inquiry by the Human Rights Commission of Malaysia (Suhakam) into the disappearance of the pastor and three other people in separate incidents.
One of the points raised by Gurdial was that it was Pastor Koh's children instead of the police who obtained CCTV recordings of the abduction from the houses near where the incident occurred.
"They are ordinary citizens doing the work the police should have done," he remarked to Tan Sri Khalid during the inquiry.
Khalid agreed with him that this was not acceptable conduct by the investigators.
Asked why police focused more on the alleged proselytisation of Muslims by Koh, Khalid said they had to investigate every lead and look at the case in its entirety.
"But that doesn't take us away from the main investigation of the abduction," he added.
The investigators had to delve into the background of the pastor and his activities, added Khalid who retired from the force in September.
Koh, 62, was abducted from his car by a group of men along Jalan SS4B/10 in Petaling Jaya at about 11am on Feb 13 while on his way to a friend's house.
His silver-coloured car bearing the licence plate ST5515D has not been found.
Earlier on Monday, his son Jonathan said Koh's mobile phone signal was last detected about three hours after he was abducted.
He said a "technical officer" from the police had told him that this signal was detected at 2pm at Taman Mayang in Petaling Jaya on Feb 13.
He told the inquiry that the police, however, did not find anything there.
The inquiry resumes on Nov 2.