Helen's sister went missing eight years ago. To this day, no-one knows where she is.

Approximately eight years ago, on the second of April 2008, my family experienced a tragedy.

Back then, the nine of us lived together under one roof in a suburban Melbourne house. There was Grandpa, Grandma, Dad, Mum, my older sister Sally, my two younger sisters, and my brother.

We were the typical Chinese family. We respected our elders, came home on time for dinner, helped out with the family business when we could, kept face and studied hard.

The day before Sally disappeared, she, my boyfriend, my brother and I played tennis together. Afterwards we went home as usual, had dinner together as usual, then locked ourselves in our rooms as usual.

The next day, I went to work and everyone else did the same. That same morning, I received a call and was told Sally hadn’t shown up at work. Initially I shrugged it off, assuming she was just with her boyfriend.

However, as the day progressed it was clear Sally was nowhere to be found. She had disappeared.

What happened after that was a blur. The family was frantic; everyone was emotional, there were tears, anger, silence and pain. Desperation of all things consumed us all. We were desperate for answers.

We spent hours driving around in the hopes of finding Sally in a park, on the street, at her favourite places. We phoned businesses to let people know she was missing. We ransacked her room to find any indication of where she might have gone. We accessed her Facebook account and contacted all her friends. We hired a private investigator. We turned to fortune tellers and psychics and went to temples to pray.

It was a difficult time for us all.

To this day we have not located Sally, nor do we have any answers as to what happened to her. My family, my friends, friends of Sally and the community she created have continued to live their lives not knowing. Sally’s sudden disappearance has left a hole in everyone’s heart.

Sally was my big sister. She was a respectful, warm, loving and put others above herself. I looked up to her and wished we were closer. She had the ability to bring people together in her community.

From the outside, she seemed to have it all.

To have her just vanish one day was more shocking than you could imagine. The questions forever burn: where is she? What happened to her? Did she choose to leave? Or did the worst happen?

The only thing we do know is that at least one person in this entire world knows something about where she is, or why she left, or how she disappeared.

People wonder – were there any indication or signs of her wanting to leave? I wouldn’t scream 'yes', but it did happen three months after her return from Beijing, where she'd lived for a year. Right after coming home she resumed helping mum and dad out at the family business, spent time with the siblings, and it seemed like everything was back to normal.

Yet in hindsight, if you had asked me if anything was out of the ordinary I would have named one moment.

It was a passing comment Sally made when we were in the car together, where she shared with me that she was sick of the curfews imposed at home and alluded to a desire for more freedom. At the time I was quite surprised by her remark.

This was my older sister. My sister, who was so dedicated to her family and understood exactly her responsibilities in the family, had just confessed she wanted more freedom? The comment was odd but I nudged it off.

People can do extreme things when they are desperate; things that inadvertently hurt another. The private investigator subjected me to a lie detector test, which I failed. Not long afterwards I was taken into their office on short notice to be interrogated. At the time I was 21 and I had no idea I had rights to leave that room.

Instead, I was led to believe my whole family suspected I was hiding something; that I knew where Sally was, that I would go to jail if I didn’t cooperate and that I was a liar. My life was crumbling in front of me as I endured the interrogation by the many people there.

Being told you know something, despite knowing nothing, was suffocating and mentally challenging. I was in tears. As hard as it is for me to admit this, I wanted to end my life.

My life after Sally’s disappearance has been full of pain and regret. Every time I’ve thought of her I have cried and experienced stabbing pains in my head. I would ask myself, 'Why me? Why Sally? Why did Sally leave? What happened to her? What is she doing? Is she in pain? Is she hurting? Is she OK?'

This was the impact Sally’s disappearance had on a 21-year-old. I have since sought counselling and have been able to continue life acknowledging Sally and my past without anchoring myself to the pain I felt at that time.

This was my frayed edge.

A few words of advice for someone living with the endless torture of not knowing: Look around you, your family, loved ones, friends and ask yourself, do you really know them? Have they shared with you their feelings about life?

When I recollect my conversations with Sally I realise I didn’t know my sister that well at all; at least not on the inside. I didn’t know how she truly felt about coming back from Beijing, how she felt about working for Mum and Dad, or how she felt about living at home again. Sally was a reserved person and never openly shared her feelings. So, focus your attention on those you don’t know well because they may be suffering in silence.

Listen to your loved ones particularly listen out for signs of distress. Months before Sally returned from Beijing she mentioned her desire to extend her stay in Beijing. Thinking little about it, I told my parents, which made Sally extremely upset. Don’t shrug it off when you see your loved one upset; take the time and effort to understand why.

For those thinking of leaving home, think about the damage your absence will create to the loved ones left behind. When Sally went missing, I witnessed my family in states I’ve never seen before: my grandfather crying, my dad confused between anger and tears, and my mum as I have never seen her before. One night as she was crying in agony, she ran from inside the house towards the pond in our garden and jumped. She then continued to sob, soaking in the water with fish surrounding her. Seeing my mother in this weak state left me crushed and has scarred me for life.

Stay connected with the people around you, whether it be through a phone call, message or a meet-up. Sally had such a large network of family and friends that she was always connected with someone on a daily basis. It was because of this we were able to identify that she was missing straight away. When a person goes missing, every minute counts.

For the families out there with missing people in their lives, continue to have hope, as hope is all we have of seeing our loved ones again. Cherish the memories you have of those missing people and do not let blame, suffering and regret linger in your lives. Your families, friends and the community are here to help you through the tough time and there are support services available for these families.

I will be forever grateful to the efforts by the Australian Federal Police in creating awareness for the impact of missing persons to the community. Missing people leave frayed edges in our lives, but if we work together to prevent them from going missing and stay connected, the community will be better off.

This is an edited version of a speech Helen Cheong delivered for National Missing Persons week. For more info go here.