The 60-year-old was discovered in a water tank on his property near Yass last Thursday, November 5 and police have said that until the coroner's report is released, the cause of death is yet to be confirmed.  

However, in an interview with the Tribune earlier this week, his younger sister Kate O'Brien said she believes he took his own life on the morning of October 5.

The man, who shared his time between Yass and Canberra, went missing from his Reardons Road property and an extensive police search revealed nothing in regards to his whereabouts.

On Thursday November 5, while working at the property, his partner Lynn went to move an empty plastic water tank but was unable to because it was too heavy. After dismantling some fixtures she checked inside to find Mr Watkinson's body.

Mrs O'Brien said she believed her brother had climbed into the tank and suffocated. 

"What I can say is that Lenny planned it and I just can't believe it got that bad for him, we all thought he was happy, we were wrong, I suppose."

She said she was at a loss as to why he would want to do this.

"This is completely my opinion remember, but I think Len put everything into his property, and he forgot about his other leisure activities, riding his motorbike and spending time just with his mates I am concerned that he didn't have other outlets. 

Despite the fact they didn't find him, Mrs O'Brien sang the praises of all police officers involved.

"The police have been absolutely wonderful, they searched for him as if he was one of their own. They listened to all our ideas, and theories of what could have happened to Lenny, I couldn't fault them."

Mrs O'Brien also wanted to shine the light on men's mental health problems as a whole.

"There is such a horrible stigma here when there really shouldn't be. It's a health problem and men need to be able to talk about it. We really need to tackle this.

"Everyone needs to know that no matter how bad things get, there is always someone who relies on you and loves you."

She also wanted to thank the area for all the help they had provided over the last month.

"I'd like to thank the Yass community for the compassion that they have shown me and my family, I've had shop owners step up and do things for me, people at work have been great and even people that I don't know at all have come up and spoken to me. It just shows how wonderful this place is."

Support is available for anyone who may be distressed by phoning Lifeline 131 114, Mensline 1300 789 978, or beyondblue on 1300 22 4636.