'It can't keep going down': Mandurah's top cop says crime below five-year average

The serious incidents from the weekend included the mugging of a 13-year-old boy, who was allegedly bashed and his watch stolen, and the assault of a 71-year-old man setting up his fresh produce stall on Smart Street mall.

Greenfields man Brodie Adam Kiernan, 20, is due to reappear in court next month accused of allegedly stabbing another young man in a fight outside Norma Jeans nightclub on Sunday morning.

He has not entered a plea to the charge.

Mandurah District Senior Sergeant Darren Hart shared an insight on crime trends at a workshop on June 1, where community leaders discussed ways to make the city safer.

Senior Sergeant Hart said there were 5505 assaults in Mandurah between 2012 and 2016.

He said reports were "trending downwards" with 1044 reported assaults in 2017 and 945 reported assaults in 2018.

"In terms of assault offences, from July 1 last year to now, personal assaults are about 340," he said.

"In a community of about 87,000 people, your chances of being the victim of a personal assault are very slim indeed.

"The majority of those cases are when the parties are known to each other, like the neighbour next door or two friends who have had too much to drink.

"Your risk of being the victim of an assault, putting family violence aside, is very small."

Senior Sergeant Hart said crime was "up slightly" compared to the previous 12 months, but lower than the five-year average.

"At some point it is going to plateau and turn a bit the other way, and that is effectively where we are at the moment," he said.

"It is up slightly, but in terms of where we stand at the five year average it is down.

"The last two years we have had a continuous downward trend in terms of reported offences.

"Inevitably it can't keep going down."