The scene of the shooting in Craigavon
A 37-year-old man has been charged with the murder of Constable Stephen Carroll in County Armagh earlier this month.
Constable Carroll, 48, was shot dead as he answered a call for help in Craigavon on Monday 9 March.
The man is also charged with having a firearm with intent to endanger life.
He is to appear in court on Wednesday morning. Earlier on Tuesday, a 17-year-old youth was remanded in custody charged with Constable Carroll's murder.
The youth was also charged with having an assault rifle, membership of the Continuity IRA and collecting information of use to terrorists.
He appeared at Lisburn Magistrates Court which was told he made no reply to the charges, but his lawyer said he would deny them.
The court was told that the youth had been in custody for 13 days and during that time had refused to speak during police interviews.
The charge sheet read out in court stated that he was in possession of an assault rifle and 26 rounds of 7.62 calibre ammunition.
The youth, who cannot be named for legal reasons, was remanded in custody to appear by a video link at a court in Craigavon at the start of next month. There was no application for bail.
On Monday, two men, aged 27 and 31, who were arrested last week in connection with the murder were released without charge.
Three other people are still being held over the murder.
Constable Carroll's murder came just two days after the killing of two soldiers at Massereene Army barracks in Antrim.
They were Sappers Mark Quinsey, 23, and Patrick Azminkar, 21.