CAPE TOWN - Justice Portfolio Committee member Glynnis Breytenbach is calling security company G4S disingenuous.
She says she doesn't buy its explanation to not appear before them.
The company's lawyer told the committee that Parliament needs to issue a summons before it will appear.
In the year since Thabo Bester's escape from prison, no mention of the incident was ever reported to Parliament's Justice and Correctional Services Committee.
The oversight body says G4S and the Department of Correctional Services both have serious questions to answer on their failures.
Breytenbach says not only is this a clear dereliction of duty, but it has also put many South Africans at significant risk.
READ: Thabo Bester | G4S to be summoned over Bester's escape
"It's the duty of the committee to A, know about these things and B, inquire about them and this happened almost a year ago and yet this was never reported to the committee," she said.
"Not once in all the appearances in between now and a year ago when Bester escaped has this ever been brought to the attention of the committee. Not by G4S, not by the office of the minister, not by Department of Correctional Services.
"So we have serious questions about that. It appears that some of them, or all of them were not even aware of the fact that he escaped, until quite recently were saying that he died in his cell. So how exactly that happened, when the DNA results apparently were available quite a long time ago, it remains a mystery and that's certainly something we're delving into quite deeply."