it didn't add up. >> co-lead investigator tom fassbender worked alongside local sheriff's deputies but a different agency -- the wisconsin department of justice. this is the first time he's responded publicly to the accusations against him and his law enforcement colleagues. did you have any kind of vendetta against steven avery? >> absolutely not. i didn't know steven avery, didn't know his family. never been there. >> fassbender bristles at the idea the local investigators could have done anything unethical. >> the people that were there that i worked with were hard-working. they only wanted to do the right thing and to do this investigation the right way. >> is it possible that that blood could have been planted? >> no. everything, all the evidence says no. >> fassbender notes that a chemical called edta had been used to preserve avery's blood in the vial. and that at trial, tests showed no presence of edta avery's blood found in the suv. >> it didn't match. >> fassbender's argument, since that blood found in the vehicle didn't contain the chemical, it couldn't have come from the vi