The video of the dogs in front of the home with LE is dated July 2.
http://www.hlntv.com/video/2015/07/02/doctor-teresa-sievers-murdered-home-family-out-town I'm not sure when the house was released back to MG.
Re: the report from neighbors that investigators were back taking samples from the dogs last week,
I wonder if evidence of something other than dog hair (dog poop?) is at issue now whereas on July 2, there was no reason to swab for saliva. On a personal note, I lived in an apartment complex that required DNA swabs for all pets in order to deter people from not picking up their dog's poop. Dog waste that was not disposed of would be tested against the saliva samples, and the offending owner would be fined once a match came back. I'm inclined to think that the search of the dog park is related to dog poop/DNA as well.