A Pennsylvania state trooper has been charged in connection with the fatal shooting of his pregnant wife.

Joseph Miller, 36, claimed he was cleaning his gun when he accidentally shot his wife JoAnna, who was 24 weeks pregnant at the time. The incident happened in 2014.

He first told detectives that he was up to 10ft away from his wife when the gun went off, later changing that to 2ft. But tests revealed on Friday that the gun was 3-6in from JoAnna's head when it was discharged.

The transcript of a 911 call made by Miller after the incident recorded him saying: "I, ah, was cleaning. I was about to clean my gun, and I didn't realise there was a round ... I shot my wife."

In the background, Miller can be heard telling the couple's children: "Guys, guys, guys, it's OK."

JoAnna was rushed to hospital but died after doctors delivered a baby girl via caesarian section. The baby girl, Gillian, died shortly afterwards.

In June 2014, the shooting was recorded as accidental but negligent by the district attorney's office.

However, the investigation stayed open as further evidence was examined – leading to ballistics and forensic tests proving that the gun was much closer to the victim's head than had been claimed.

In interview transcripts, detectives ask Miller: "Did you intentionally shoot your wife?"

He replied: "I did not. It was an accident. I love her to death."

Miller was arraigned yesterday (17 March) on two counts of involuntary manslaughter.