I'm now quoting from a post of 2011. ( Spot the mistakes )
" Quote: The re-submitted swab did have a different identifying mark,but only partially. There were 3 copies of the same submittal form for the lab. DS Davidson testified that it was a mistake on his part to write down 2 identical numbers ( DHL/33 ) and then somehow write down the incorrect number ( DHL/44 ) on the 3rd form.
He also wrote down the wrong time that the swabs had been taken ( 11am rather than 3.15pm ) another mistake on the same form.
DS Lovell.the police liason officer at the lab.,whose job it is to check the submitted paperwork with samples, also stated he made a mistake when he didn't notice that there were two different indentifying marks on the paperwork.
That's already 4 mistakes ( DS Davidson 2, DS Lovell 1 and whoever packaged swab with guns,1 ) on a solitary and pretty crucial evidence in a quintuple shooting. Unquote ".
Particles of lead,barium and antimony fused together are unlikely to remain on a shooter for long.