In a statement on Friday, Western Cape police praised the Milnerton detective who made the arrests.
The detective started his investigations following an attempted murder in Joe Slovo Park on March 4.
During the investigation, the detective followed up on leads and identified the man who had allegedly shot and wounded the victim, spokesperson Segeant Noloyiso Rwexana said.
The three Somali men arranged to meet with the detective and offered him R20,000 in cash as bribe for the disappearance of the docket, she said.
The detective agreed to the arrangement and notified his commanders of the proposed meeting.
Police planned an operation and set up a meeting on Thursday.
During the meeting, the detective was handed R5 000 in cash, Rwexana said.
The three men were subsequently arrested and are expected to appear in court soon on charges of bribery. One of the three men is also facing an attempted murder charge for the Joe Slovo Park incident.