A judge overturned a criminal conviction of a man accused of attempting to murder a US police officer on the basis that the ShotSpotter crime-fighting tool used by the police was not reliable enough.

Silvon Simmons was stopped and shot in the back three times by Rochester, New York, police looking for a suspicious vehicle. 

Simmons was charged with firing first at officers when running away, despite ShotSpotter initially not detecting any gunshots and the system's algorithms ruling that the sounds came from helicopter rotors.

ShotSpotter analyst Paul Greene later said that there had been four gunshots - the number of times police fired at Simmons, missing once. 

However County Court Judge Christopher Ciaccio ruled that ShotSpotter was unreliable, reversing the weapons possession conviction against Simmons. Simmons had earlier been acquitted of attempted murder by a jury.

Simmons spent eighteen months in jail before his acquittal and since the incident has suffered from anxiety, depression and other mental health issues.