A man charged over a double shooting at Fantasy Fine Line tattoo parlour in Maidenhead had the case against him dropped on Tuesday.
Simon Sarkissian, 41, of Melville Road, London, had been charged with assisting the commission of an offence over the attack in St Mark's Road on April 11.
But a judge at Reading Crown Court concluded there was insufficient evidence against him.
Three men are due to face trial at Reading Crown Court from January 9 in relation to the shootings.
Anthony Cooke, 31, of Union Street, Bedford, and Leon Doorman, 29, of Hinton Walk, Dunstable, each face six charges: conspiracy to rob, possession of a firearm with intent, two counts of attempted murder and two counts of wounding with intent.
Joseph Anthony Gentle, 22, of no fixed abode, is charged with conspiracy to rob and possession of a firearm with intent.
A fourth man - Sean Fury, 29, of Essex Close, Luton - will be sentenced for a drug offence when the trial concludes.
He had initially been charged with conspiracy to murder but this was changed to conspiring to supply a controlled drug and he pleaded guilty in August.
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The Met Office has issued a yellow alert for Windsor and Maidenhead, Slough and Wokingham, warning that rain moving eastwards across the south of the country may turn to snow in some places.