HORRIFIC details have emerged about how a woman and her two daughters were separated before being murdered near Warwick in 1974.

A witness yesterday described how Barbara McCulkin and her daughters Vicki, 13, and Leanne, 11 went for a drive with Warwick man Vincent O'Dempsey and Torbanlea man Garry Reginald Dubois on the night they were murdered.

The men brought them to Warwick, and separated the mother from the girls before Mr O'Dempsey strangled Barbara, a committal hearing has heard.

Mr O'Dempsey then asked Mr Dubois to help him kill the children but Mr Dubois claimed he could not do it, the court was told.

Mr O'Dempsey, 77, and Mr Dubois, 68, have been charged with murdering the McCulkins. They also face other charges including deprivation of liberty.

One of their former associates, Peter Hall, yesterday gave evidence about how he was at Mr Dubois's house with another man, about to go for a drive to scout places to break into, when Mr Dubois told them what happened to Barbara and the girls.

"I'm not sure which exact words he used but he told us what went down in relation to the three victims, how they went for a drive ... they ended up in Warwick somewhere," Mr Hall said. "He said when they got up there they separated the girls from their mother and Vince took the mother away and strangled her."

Mr Hall said they buried them somewhere in the area.

Mr Hall, who also has a criminal history and has previously faced court at Warwick and Caboolture, admitted he had previously lied when giving evidence at the Crime and Corruption Commission's hearing held last year into the McCulkins' disappearance.

He said he came forward with the information because his perception had changed and that he wanted to tell the truth.

The committal hearing continues.