This was after he'd turned up at his Alison St home where she was staying, saying the baby wasn't breathing.
"I was trying to stay calm, he was very still, not moving, I couldn't tell if he was breathing ... It looked like he was still alive, he was warm."
She testified that shortly after Karlos' death Roberts instructed her to say he had been a victim of cot death, telling her things weren't looking good for her because of her condition (post natal depression).
She felt threatened and worried, fearing CYFS would step in and she wouldn't see her family again.
"I was very upset, confused, I didn't know what to think, what to do, what to say."
When a police officer interviewed her she told him Roberts had spent the night with her and the children at Alison St, admitting that was contrary to what she'd told another officer soon after Karlos was pronounced dead.
The jury previously heard Roberts and his ex wife were sharing the twins' care despite living apart. The weekend Karlos died the older woman was in Christchurch.
Probed by Crown solicitor Amanda Gordon, Stephens denied doing anything to hurt Karlos, she hadn't shaken him or hit his head on the floor or side of the couch. She agreed while they were together she hadn't seen Roberts do anything to hurt him either.
The jury were played a tape recording of a phone call Stephens made to Roberts on August 31 last year.
In it she told him results relating to Karlos' death confirmed he hadn't died from an illness, that he'd been killed. She said "I'm just waiting for them to come and arrest me."
Roberts responded that was all s*** ... stressing he was not running away from anything "We're not runners."
Stephens replied she was freaking out and had done nothing wrong. "I wasn't even there."
Roberts told her the truth lay with the Coroner.
Cross-examined by Robert's lawyer, Max Simpkins, Stephens agreed she'd suffered from post natal depression and had difficulty bonding with the twins.
She'd let them be cared for by Roberts' ex wife, helped by their daughters, because they were responsible girls.
Stephens denied that Roberts and his family had provided all the equipment for the twins, insisting she'd given him about $300 or $400 to get everything the boys needed. Pressed, she accepted that was something she hadn't mentioned until today.
Asked about CYFS involvement with her family, Stephens accepted they hadn't initially been happy the twins were with Roberts but as time passed that changed.
The trial, before a jury of six men and six women, is continuing.
