It was claimed that Sweeney helped his friend dispose of some items taken from the Bayliss house.
Today, the eighth day of the High Court trial in Christchurch, the Crown withdrew the attempting to obstruct the course of justice charge.
Sweeney then pleaded guilty to being an accessory after the fact of burglary and arson.
He will now be sentenced at a later date.
The jury will now be left to judge whether McLaughlin is guilty or not of murder.
Last week, Jade's mum, who is the former partner of McLaughlin, gave evidence that the schoolgirl had "no respect" for her alleged killer and used to mock his speech impediment.
Tina Bayliss also revealed that McLaughlin professed his love for her on the first day they met, while he was working a second job as door security at a Christchurch nightclub in September 2011.
After four to six weeks they split up after McLaughlin had a row with Jade, the oldest of three children, had written 'Ford' on his 'Holden' T-shirt.
Pathologist Dr Katherine White last week told the court that Jade had died of strangulation - before the fire broke out.
The trial before Justice Graham Panckhurst continues.
