Co-lead investigator Tom Fassbender received information about Brendan Dassey having bleach steans on some jeans and that being the result of cleaning the garage floor of his uncle Steven Avery. Acting on that information Fassbender went to the motel where Brendan and his mother were staying. Fassbender inquired about the jeans and Brendan said he had worn a pair of jeans on the 31st of October while cleaning "dark red stains" from his uncle's garage and had bleach stains on them.
Together with Brendan, special agent Fassbender went to the Janda residence to pick up the jeans. Once inside, Brendan led Fassbender to the jeans.
Culhane tested the jeans, along with a jacket also belonging to Brendan, for the presence of blood. The items came back negative for the presence of blood. Culhane did not test the items for the presence of DNA.
Supporters of Avery and Dassey claim that if bleach came on the jeans, then there should have been blood on it as well, if that is what Avery and Dassey were cleaning that night. The fact that the jeans came back negative for the presence of blood is evidence, according to Avery & Dassey supporters, that no blood was cleaned that night and Avery & Dassey were framed.
On the other hand, if they were cleaning something other than blood, another red fluid, then shouldn't that, according to this logic, be on the jeans instead? At trial, Brendan Dassey explained he made sure he did not come in any contact with the red fluid, which is probably why his jeans were clear of red stains.