I am sure most of you remember the case where this family lived in a trailer (somewhere out west, possibly CA). One night they awoke to a fire, which ended up killing one of the daughters and injuring others. One of the girls was found later to have been shot with a shotgun, and one of the other girls says that their own brother did it.

Anyway, the fire was ruled arson, the shotgun was found and the son/brother was caught one night, during the investigation, trying to sneak into the building where the shotgun was being stored.

I was wondering if there was any update? I remember the suspect, the son, appeared in the segment in silhouette. Obviously he never was convicted of any crime. His own parents seem convinced he is guilty, though.

All the evidence points toward the son, but I was wondering if any arrests had ever been made of any other suspects?

I think i remember the case you're talking about. The suspects name was 'Donnie' I think and he was accused of the arson/murder of his half-sisters?
That took place I think in Humboldt County, California.

As far as I know, I haven't seen an update on the show or otherwise......I'll try 'googling' it and see what comes up.

Donnie is correct. Donnie Hansen to be specific, the sisters were Jill and Julie Hansen. Donnie was visiting from Fortuna, I don't recall the city the sisters and the parents lived in. Actually, both had been shot by a shotgun, but I don't believe either died from those particular afflictions. One perished in the fire and the other died when an air bubble entered a tube that was inside her at the hospital.

Donnie was tried but wasn't convicted. He appears to be way guilty, but I'm guessing that he got off because the evidence against him, while massive, was all circumstancial. There were rumored to be two unidentified persons at the trailer that night, most likely accomplices of Donnie, but they have never been charged or identified.