Ken Kratz speaks out about controversial Making a Murderer blood vial

The dispute over the Steven Avery murder conviction has gone far beyond Making a Murderer itself.

The Netflix documentary has drawn criticism from the prosecution, while Avery's own defence lawyers have spoken out about some of the comments to come to light since the show aired. And now a new documentary will present UK audiences with more from prosecutor Ken Kratz, lawyer Jerry Buting and others. Steven Avery: Innocent or Guilty? will air on the Investigation Discovery channel, and sees Buting address claims that Avery - whose arrest and trial for the murder of Teresa Halbach was the subject of Making a Murderer - lured the photographer to his auto salvage yard. Both Buting and Kratz also comment on the controversial vial of blood, which some had suggested may have been planted in an attempt to frame Avery. "Regarding the hole in the vial (it was shown that a vial on file of Avery's blood had a hole in it, which made many suspect his DNA was planted) this is one of the more irresponsible claims that's in this particular film," Kratz is quoted as saying in The Daily Record. "The blood gets IN the purple tube by creating a hole," he added.