Katrina Bohnenkamp was last formally identified aged 15, by police officers in the early hours of October 26 in 2012 at her father's Strathfield boarding house.

She had been moved around several foster carers and homes since she was a toddler but had recently been showing up at all hours of the night to see her father.

On October 25 of 2012, police conducted a search warrant on Maiko Bohnenkamp's home after he was allegedly involved in a machete attack.

Granted bail soon after, Mr Bohnenkamp says he returned home and saw Katrina, sitting on the couch with his partner before he passed out.

Since then the regular Facebook user has never logged online, received any Centrelink, Medicare or welfare payments, accessed her bank account, nor is she recorded leaving the country.

"After that date...all the relevant activity you would expect from someone who is still alive ceased," counsel assisting the coroner Philip Strickland SC told the inquest.

"The circumstances of her death are suspicious. My submission is they are highly suspicious."

Mr Strickland questioned why her father, his partner and her stepbrother, the last people to see Katrina alive, had taken months to reach out to her sisters to let them know or ask for help in their search.

One of those sisters, Jade Simpson, broke down on Wednesday describing Katrina as "spirited and lively" with dreams of becoming an equine vet one day.

"She had goals and determination to get there if she had been given the chances," Ms Simpson told the court.

"She had so much to give, so many places to see, she would have been 22 now....finally free of the system, free of struggle."

On Tuesday Mr Strickland replayed video footage of Rick Olden, who said he saw his stepsister's "lifeless" body with her father standing over it.

Olden claims the pair - both long-term drug addicts at the time - then lay her unconscious body on a couch that was disposed of three weeks later. That was the last time Olden says he ever saw Katrina alive.

About a week after Katrina disappeared, both men's phone records completely ceased over the same three-day period. In earlier evidence Mr Strickland suggested the mobile phone data appeared to have been wiped.

But Mr Bohnenkamp has vehemently denied acting violently towards Katrina.

On Wednesday he turned to Olden who was appearing via video link from prison, and asked: "What have you done to my kid?"

Mr Bohnenkamp says one of the last times he had a father-daughter moment with Katrina he had questioned her about revelations she was using ice.

He denies ever losing his temper over Katrina's drug use, saying it hit a nerve and made him feel guilty.

"When I say I lose it, I lose it because I don't feel adequate enough as a dad," Mr Bohnenkamp said.

Deputy state coroner Carmel Forbes is due to hand down her findings in the coming months.

Australian Associated Press