Alex�s ashes were stolen last week along with about $30,000 of jewellery, including Ms Cheung�s engagement ring, from her home in Noranda.
Ms Cheung�s husband and three sons came home from school on May 4 to find the back door had been pried open and the home ransacked.
As soon as Ms Cheung got home, she raced to her bedroom to check if the box that contained Alex�s ashes was where she had left it on her bedside table.
The City of Swan Councillor is devastated that the box with her son�s ashes, birth and death certificates and umbilical cord clip has been stolen.
Ms Cheung, who lost Alex 10 years ago on December 5 in tragic circumstances, said this was like losing him a second time.
�Alex will always be a part of our family and even though he�s not here anymore, he�s still my son and he has brothers who love him and a mum and dad who love him,� she said.
�He was a part of our life so his ashes are a way of keeping him close to us.
�I feel like I let him down a second time. I just want him to come home again. If they can return him, there will be no questions asked.�
Another box that was stolen contained the baby teeth and hospital identification bracelets of Ms Cheung�s three sons.
She said these held no value to anyone else and that she just wanted them back.
The mother of three said she was now having to reassure her children that they were safe.
�They were freaking out, they were so scared that there were people in the house,� she said.
�Our neighbours across the road said that they heard them screaming. My four-year-old keeps asking �why did bad people come and take baby Alex?
�It breaks my heart; every day they discover something else of theirs that has been taken.�
The burglary has tested Ms Cheung�s Catholic faith, but she has been left with one piece of jewellery reminding her to hold on to hope; a necklace with a gold cross pendant.
Alex�s ashes were in a silver/white hand sized box, with a rainbow butterfly image. It was wrapped in a white drawstring bag, similar to a jewellery bag.
Anyone with information has been asked to call Crime Stoppers on 1800 333 000.