The case against a man who was accused of murdering a police officer as he was investigating a burglary has been dropped, a court has heard.
Newlywed PC Andrew Harper was killed after being dragged along a road by a vehicle in Sulhamstead, Berkshire, on 15 August.
Jed Foster, 20, from Pingewood, has had his case “discounted” after further police investigation, prosecutors said.
Three teenagers charged with murdering PC Harper also appeared in court.
Prosecutor Jonathan Polnay told the Old Bailey: “The Crown Prosecution Service concluded the full code is not met. There is a not a realistic prospect of conviction.
“Proceedings against Mr Foster cannot and should not be continued.”
Henry Long, 18, from Reading, and two boys, 17, who cannot be named, are accused of murder and conspiracy to steal a quad bike.
Appearing at the Old Bailey, Mr Long was remanded in custody, while the two other defendants were remanded in youth detention accommodation.
A trial date has been set for 9 March next year.
Thomas King, 21, from Basingstoke, has been charged with conspiracy to steal a quad bike and also appeared.
He was granted conditional bail.
PC Harper, 28, was killed on the A4 Bath Road as he attended a reported break-in.
A post-mortem examination found the officer, who got married four weeks earlier, died of multiple injuries.