IMO, It would not be unusual for authorities to find any way they can to get someone incarcerated for other offenses while they continue to work on building a murder case against that person. Especially if they have very little physical evidence to tie that person directly to the murder itself. This approach would allow them to get the person off the streets and continue to build their case and search for evidence. IMO, I think there is very little physical evidence that has been discovered in this case, i.e. no DNA of the perp, no fibers directly on the victims, etc. IMO, there may be footprints but those either haven't been matched to anyone OR they could be explained away by a defendant in a court of law. Bottom line, I do think LE believes they know who committed this crime but they don't have enough of a case at this point to be able to get a conviction in a court of law so they are doing the best they can to protect society and give them more time to investigate and build a stronger case. ALL JMO.