Police have detained a man to assist in the investigation into the disappearance of Pastor Raymond Koh Keng Joo in Petaling Jaya since Feb 13.

Without disclosing where the suspect comes from and his age, Inspector-General of Police Tan Sri Khalid Abu Bakar said the man was arrested last week in the northern part of the peninsula.

"So far, only one suspect has been detained and I cannot reveal more on the matter.

"We will not close this case and I stress that PDRM (Royal Malaysian Police) investigates all cases and that is our task," he told a news conference after the launching of a blood donation drive held in conjunction with the 210th Police Day celebration in Bukit Aman, here.

Khalid said in investigating the missing pastor case, police faced difficulty during the preliminary investigation due to interference by certain quarters.

"The interference had impaired the case investigation. I had informed to let us first investigate this case and not to give it too much publicity....when there's too much publicity, there can arise many flaws," he said.

Khalid said the investigation was not just focused on pastor Koh's disappearance but also on claims by the public that he was carrying out activities to turn Muslim individuals into apostates.

"We need to investigate every police report received to ensure justice and not raise questions among the public," he added.

Meanwhile, three activists, Thomas Fann, Sevan Doraisamy and Rama Ramanathan from the Citizen Action Group on Enforced Disappearance (CAGED) were today called by Bukit Aman police to assist in the investigation into the disappearance of Amri Che Mat, pastor Koh, and Joshua Hilmy and his wife Ruth.

CAGED spokesman, Fann said they were called to the federal police headquarters following their statements on the organisation at a press conference on May 5.

"We were asked more than 20 questions on CAGED and on those related to the reported missing person cases.

"We only answered what we felt we should and we will continue to follow closely the reported cases of these missing persons until they are resolved," he said.

-- BERNAMA