Scott Peterson is good famous example of junk dog-scent evidence ( Laci was actually killed by serial killer Edward Wayne Edwards, who even left a signed confession on the internet ).
Another example is bogus time-of-death estimates which underestimate uncertainty, see here https://geebee2.wordpress.com/2015/07/06/estimating-time-of-death/ ( another Edwards murder for which someone else was convicted ).
The veteran law enforcement, law and science blogger at Grits for Breakfast’ in TX has some sharp points to make about his picks for the worst in forensic methods. There are more than just bitemark “interpreters” which he includes in this list.
He does touch about the ‘War on DNA mixtures” examiners who overstated their confidence levels by a power of about 10 to the seventh power.