Accused wife killer Gerard Baden-Clay seemed visibly upset as his two children dealt with their mother’s absence in distressing police interviews.

Brisbane woman Allison Baden-Clay’s children sobbed as they told police about the last time they saw their mother.

Heart-rending recorded police interviews with two of the Baden-Clays’ three young daughters were shown during the trial of former real estate agent Gerard Baden-Clay on Wednesday.

The primary school aged girls were interviewed on the afternoon of April 20, 2012, hours after Baden-Clay contacted police to say his wife hadn’t returned from a walk.

In Brisbane’s Supreme Court, the 43-year-old has pleaded not guilty to his wife’s murder.

Baden-Clay became visibly upset during the evidence and repeatedly wiped at his eyes with a tissue or handkerchief.

“I saw her last night in my room. She was saying goodnight to me,” the middle child told police about her mother.

The girl dissolved into tears when she told detectives her mother had sung her a song while tucking her in.

She told them she became worried the following day “because she hasn’t come home for a long time”.

Both girls said they saw fresh scratches on their father’s face that morning which he’d told them he’d done shaving.

They also said their parents didn’t fight often and things had seemed normal the previous night.

Earlier, friends and colleagues testified Allison Baden-Clay was happy and upbeat the day she vanished, despite a history of depression and anxiety.

The court heard she chatted with other mothers at school drop-off. She became enthused after receiving real estate coaching at her husband’s business, where she worked part time.

“She seemed happy that morning, actually, she was very happy,” said friend Anne Swalwell, who saw her that morning at the local primary school.

The Crown says Allison Baden-Clay was dead the following day, her body dumped on a creek bank at Anstead in Brisbane’s west.

It would be 10 days before she was discovered, lying in the mud with her arms raised above her head and with a jumper twisted over her neck and head.

According to the forensic pathologist who conducted the autopsy, her remains were in such an advanced state of decomposition no cause of death could be identified.

“I don’t have any information to be confident about anything as a cause of death,” Dr Nathan Milne said, adding it probably wasn’t from natural causes.

The only anomalies that forensic experts could find were a chipped tooth, a possible bruise on Mrs Baden-Clay’s chest and signs of a superficial wound on one shin.

Under cross examination from Baden-Clay’s lawyer, Michael Byrne QC, Dr Milne agreed Allison had elevated levels of an anti-depressant in her system but said higher than usual levels were to be expected in a decomposing body.

Dr Milne agreed drowning, falling from a height or overdose couldn’t be ruled out as causes of death.

The trial continues.