A teenage girl who fell to her death from a bridge in an apparent suicide pact believed care home staff could not go near her on the crossing, an inquiry has heard.
Niamh Lafferty, 15, died when she plunged more than 100ft from the Erskine Bridge into the river Clyde in October 2009.
Her fellow resident at the Good Shepherd Centre in Renfrewshire Georgia Rowe, 14, also died.
A fatal accident inquiry into the deaths was told Niamh was under the impression staff at the home could not approach her while she was on the bridge for safety reasons.
The teenager had been moved to the centre after her father, Paul Lafferty, said he could no longer cope with her and she refused to return to her mother's house.
Social worker Sandra Leonard said Niamh had gone missing from the centre shortly after her arrival in July 2008 with some other girls from the home.
She said the teenager had intended to return to her home town of Helensburgh and had walked over the Erskine Bridge without staff stopping her.
She was later returned to the centre but had formed the impression staff could not stop her walking over the nearby bridge, Ms Leonard said.
She said: "Niamh had an understanding that they couldn't approach her when she was on the bridge. She was aware they wouldn't approach her."
Ms Leonard said she understood it was part of the home's safety policy not to go near missing residents while they were on the bridge.
She said: "It was for the safety of the young person – how they might react."
The inquiry at Paisley Sheriff Court was told Niamh would return to the home under the influence of drink and drugs. Ms Leonard said she had been warned it was suspected Niamh was drinking alcohol and taking morphine while on visits to her father's house.
On one occasion, Niamh was brought back to the Good Shepherd Centre from a police station after officers found her in her father's home when she was supposed to be at the centre.
Ms Leonard said while Niamh appeared to be making progress in terms of her emotional and psychological state while at care home, she still needed support.
She said: "She would just react to situations. She was impulsive. She would just see something was wrong and just start screaming. It was almost like a temper tantrum.
"She really needed support to calm down and think through her reactions. We didn't really move on from that stage. We got to the stage where we could talk her through her feelings and her outbursts, but she couldn't always do that without support."
The inquiry, before Sheriff Ruth Anderson QC, continues.