A woman was slashed to death - all because she witnessed a murder in Sungai Way here early Wednesday.

The unidentified woman had stumbled on three men hacking an Indonesian immigrant worker to death with machetes outside a karaoke outlet in Jalan PJS 8/13 when the killers spotted her.

In the incident at 1.25am, the trio switched their attention on the 40-year-old local woman and slashed her to death.

Petaling Jaya police chief ACP Azmi Abu Kassim said initial investigations revealed the woman was killed because she witnessed the murder of the 34-year-old Indonesian.

He said three men armed with machetes and chain were attacking the Indonesian man at a sidewalk when she happened to be in the vicinity.

"At that juncture, the armed trio pounced on the woman and slashed her to death," he added when contacted by Bernama.

Azmi said initial investigations revealed the unidentified Indonesian's murder was fuelled by revenge.

The bodies were sent to the Universiti Malaya Medical Centre.