Police on Monday raided a building in Mong Kok, with sources saying the operation was linked to a murder case in Fo Tan the day before.

A 52-year-old man was killed on Sunday after he was attacked by two knife-wielding men on Lai Wo Lane.

Officers cordoned off King Hing Building at the junction of Argyle Street and Fa Yuen Street on Monday afternoon, in what's believed to be part of an investigation into the case.

The building reopened later in the afternoon.

Police did not say if any arrests were made.