He spent 27 years in the British Army with the Royal Electrical and Mechanical Engineers and 15 with the New Zealand Defence Force (NZDF).
During his career he was the development officer for the New Zealand Provincial Reconstruction Team in Bamyan province, Afghanistan, where he helped with about $150million of projects, including the construction of a two-lane highway to help farmers get their produce to market faster.
He also managed sniper rifle projects for the NZDF.
It is understood he moved from Waitati to Greymouth last December.
Tweedy, who had no previous convictions, yesterday admitted aggravated burglary at a Greymouth property, physically abusing a protected person and intentionally impeding the breathing of that person by applying pressure to her throat and neck between May 10 and 11 this year.
A charge of kidnapping was withdrawn.
A police summary of facts said a protection order had been in place against Tweedy since January 15.
At 10.27pm on May 10, Tweedy went to the victim's home address in Greymouth, armed with an M16 military-style semi-automatic assault rifle.
He approached the front door wearing blue rubber surgical gloves, camouflage pants and a hooded top pulled over his head.
Using a key to open the front door, he reached inside and cut a security safety chain.
Tweedy, described as "highly agitated", made his way to the sleeping victim's bedroom where he pointed the rifle and a torch in her face to wake her up and told her he was going to kill her.
He demanded she get up and get dressed — she tried to calm him down but saw an opportunity to escape, so tried to run out the front door.
Tweedy stopped her and dragged her back into the hallway where a struggle ensued during which he struck her across the face, causing her lip to bleed.
Tweedy then managed to place a belt around the woman's neck and began to apply pressure with it, causing her to have difficulty breathing.
"But she managed to get two fingers under the belt at the front of her neck to provide some relief to her airway," the summary said.
"The defendant started crying and became very upset.
"The victim managed to calm him down which prevented the attack continuing.
"The pair then moved into the kitchen where the victim made him a cup of tea and a sandwich."
The summary said Tweedy confined the victim to the kitchen for a "significant period of time with the rifle in hand" before eventually calming enough to put it on the kitchen bench, next to a knife, while he went to the bathroom.
The victim sent a friend a text message asking her to contact police and then sent a photo of the firearm.
As armed police were approaching the address, Tweedy walked out with the firearm and a bag and travelled to Cromwell where he was arrested without incident.
The victim sustained a bleeding lip and swelling and bruising to her lip, chin and the front of her neck, significant bruising and swelling to her chest, left hand flank, front breast area and middle stomach — the latter two were about 8cm wide and circular.
She also had bruising to both feet, both knees, her left big toe, right wrist, left forearm and right elbow.
"Emotionally the victim was terrified and collapsed into the arms of attending police when she finally managed to exit the address."
Tweedy admitted the facts, but did not provide the rationale behind his offending.
He was remanded in custody until his sentencing in October.
