Constable Carroll was from Banbridge in County Down
A 37-year-old man has been charged with shooting a policeman in County Armagh in Northern Ireland earlier this month.
Constable Stephen Carroll, 48, was killed as he answered a call for help two weeks ago.
The man has also been charged with having a firearm. He will appear in court on Wednesday morning.
Earlier on Tuesday, a 17-year-old appeared in court, also charged with Constable Carroll's murder.
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.
A group called the Continuity IRA, which disagrees with the Northern Ireland peace process, says that it was responsible for the attack.
Constable Carroll was shot just two days after two soldiers were killed at Massereene Army barracks in Antrim.
A group who call themselves the Real IRA says they carried out that attack.