Karlos' mother, Pamela Stephens, took the stand this morning for the second day, recounting the days of and prior to her son's death.
Yesterday, she had tearfully recounted how she had seen Roberts as a friend and "genuinely believed" he would be "very helpful" with her twin boys.
She had been suffering from what her doctor thought was post-natal depression and she had needed some time to get back on her feet so she allowed Roberts and his ex-wife to take on fulltime care of the boys.
On November 26, 2014, Stephens went to stay at his Alison St property to spend some time with her twin boys but he did not arrive with the boys until November 29.
He left the boys with Stephens for a time. She recalled Karlos being "feverish", "grizzly", "clingy and tired" and "just wanted to be cuddled".
This morning, she said when Karlos was in her care that day, he didn't fall down or knock his head at any time and she had not shaken him or done anything to hurt him.
She said she also had not seen Roberts hurt either of the boys that day.
Roberts had left with the boys that night. Stephens told the court that she recalled both twins had "let out a scream and cried for me" when Roberts took them away.
She said Karlos had "not looked well" when they left.
Roberts did not return with the boys that night but Stephens was woken at 7.30am to a car pulling up at "full speed".
She told the court that as soon as she saw Roberts, she knew something was wrong and when she asked him, he said: "It's Karlos - he's not breathing".
The pair "argued" as Roberts wanted to bring Karlos inside and call an ambulance, to which Stephens immediately disagreed and said they needed to get "straight to the hospital", she said.
"The child will be f**** dead in another min," she said she remembered thinking while in "panic mode".
She told Roberts to ring 111 and let them know they were coming as she held him in the back seat, she said.
She said Karlos was "floppy", "not moving" and had a "little bubble of foam out the side of his mouth". His eyes were closed.
She recalled his body was "definitely still warm".
"I honestly thought he was basically dead at that point".
She held Karlos in her arms the entire five-minute drive to the hospital from Alison St.
She asked Roberts what had happened, to which he said he had woken and found him like that in bed, she told the court.
Roberts told Stephens to run into the hospital and tell them "I found him like this", she said.
Doctors and nurses rushed to help and she said it was clear to her, from monitors, that Karlos still had "a heartbeat". She "thought he would survive".
However, resuscitation efforts failed and doctors told Stephens that Karlos had died.
She remembered that Roberts would not say anything further about what had happened to Karlos, she told the court.
Around this time, police had shown up at the hospital and told Stephens she would need to be questioned.
Stephens said Roberts told her at the hospital to lie to police and say that they had spent the week together at the Alison St address as a couple.
He told her to "make it sound like we put Karlos asleep together" and they had woken to find him not breathing. She told the court he told her to tell police she had found Karlos that morning.
It was not until August 2018, when Stephens was questioned by police again, that she told them she had made a false statement in 2014 and that Karlos had left with Roberts on the night of November 29.
Roberts' lawyer, Simon Lance, started his cross-examination with Stephens by questioning her about her relationship with Karlos and his twin brother's father.
He asked Stephens if the pregnancy had been planned, to which she responded no and that it had been a mistake. She said that the pair did not know each other well.
Lance suggested that with her four other children and finding out she had twins on the way as a solo mother, she was under a lot of pressure, to which she replied that she "definitely" was.
After the boys were born, she said she was feeling "helpless" and "hopeless" and was "having a really difficult time" facing post-natal depression.
She agreed that she was having trouble "bonding" with her twin boys at that time.
Lance questioned her about falling out with her mother as she did not like her "lifestyle" that involved partying and drinking.
Stephens said she did go out partying "occasionally" and would drink. She had also tried drugs, including methamphetamine.
She said this was always after the children had gone to bed and her mother was looking after them.
However, she did not meet Roberts out partying but instead through a friend, she told the court.
On their first meeting, she said they "had a bond".
The trial continues.
