Perth dad's murder remains a mystery

The killer of a 43-year-old Perth father who was stabbed in the neck while waiting for a bus last November remains at large.

Ian Baz Bosch was attacked by an unknown offender at a bus stop opposite the Coolbellup Shopping Centre about 7.30am on November 19 last year.

Mr Bosch, who was running some errands before taking his daughter to a birthday party, died later in hospital from his wounds.

His death had been "very traumatic" for his 10-year-old son and five-year-old daughter, the children's mother Emerald Baz said in a statement, adding that Ian was a private person who was kind and generous.

Police have renewed calls for public help, with detectives keen to speak to anyone in the vicinity that morning.

"They may have seen something which seems insignificant, but which may in fact be crucial in the context of our investigation," major crime squad Detective Senior-Sergeant Tom Mills said in a statement.

Detectives are particularly interested in speaking to a man who was walking a small white dog near the shopping centre that morning.