PCS president Datuk Seri Wilfred Bumburing’s corporate officer located on the second floor of the same building was also broken into.
The incident was believed to have occurred late Monday.
Bumburing’s press secretary Lesaya Lopog Sorudim said the suspects seemed to have a specific set of items to steal as not all valuables were taken in the incident.
He said that out of all the equipment in the two offices, only the desktop computer used by PCS secretary general Petrus Guriting, Bumburing’s laptop and his two hard disc drives containing important files were missing.
"They were specific in what they wanted," he said, adding the stolen hard disks and laptops contained all their party information.
"Surprisingly, the adjacent businesses were spared. The burglars could have entered those offices easily," said Lesaya.
He said he was startled to see papers strewn all over the place when he reached the office at about 9.30am Tuesday.
"Wires and cables for the alarm system pulled down and scattered as well," he said.
Lesaya said the intruders had gained entry into both units by cutting and bending the iron grilles at the fire exit.
He added that they were still looking through the strewn files to determine if any particular files were missing.
A report has been lodged and police are investigating the case.