HALIFAX -- The Nova Scotia government says it will call an inquiry into the deaths of a former soldier and his family, nearly 12 months after the horrific murder-suicides sent shock waves across the country.

Dr. Matthew Bowes, the province's chief medical examiner, recommended the fatality inquiry on Thursday, calling the deaths in rural Nova Scotia an "unimaginable tragedy."

On Jan. 3, 2017, retired corporal Lionel Desmond shot his wife Shanna, 31, their 10-year-daughter Aaliyah and his 52-year-old mother Brenda, before turning the gun on himself. Desmond had been diagnosed with PTSD and post-concussion disorder after completing two difficult tours in Afghanistan in 2007.

In a letter to Justice Minister Mark Furey, Bowes said the inquiry is necessary to "compel evidence and make recommendations for change."

A spokesman for the Justice Department said the minister has committed to holding the judicial inquiry, with the terms of reference and the judge set to be announced in the new year.

Two of Desmond's sisters, twins Chantel and Cassandra, have led the high-profile campaign calling for an inquiry.

"Our entire province was shocked by the deaths of Lionel Desmond and his family," Bowes said during a news conference. "There have been many questions raised by the family and the public relating to how this could have happened and whether anything could have been done to reasonably prevent these deaths."

After speaking with members of the Desmond family and reviewing the circumstances of the deaths, he said an inquiry into the case is warranted.

"The purpose of this is to look for some tangible connection between the deaths and the appearance of a failure of policy or practice which if corrected is likely to prevent future deaths of this same type," Bowes said. "It's my hope that the public nature of the inquiry and its final report will drive change."

While cautious not to presuppose the focus of the inquiry, he said the apparent lack of co-operation between government agencies will likely be a key aspect of the terms of reference.

"I was very much struck by the fact that there were many government agencies that touched on Mr. Desmond's life and I would take the view that the interconnection between all of those may well have been better," Bowes said.

Such investigations are rare in the province. The last time a fatality inquiry was held in Nova Scotia was almost 10 years ago.

Trev Bungay, a retired soldier who served in Afghanistan with Desmond, questioned why it took almost a year to recommend an inquiry into the horrific murder-suicides.

"It's about time," he said in an interview from Fredericton, N.B., adding that Ottawa and the province "wasted a lot of time blaming each other and trying to figure out whose fault it was."

Still, Bungay said he's hopeful the inquiry will provide some badly needed answers for the family, as well as ensure better services are in place for veterans in the future.

"At least the family can have some sort of closure. For them this has been a nightmare," he said. "They want answers and this is how to get them and more importantly how to stop this from ever happening again."

Family members say Desmond was a radically changed man when he was medically discharged, and returned home to Upper Big Tracadie in 2015. They say his outgoing sense of humour had dimmed and, more importantly, he seemed withdrawn and in a defensive posture much of the time, as if he was still in combat mode.

Within hours of the killings, relatives came forward to complain Desmond did not get the help he needed, and they demanded a public inquiry to determine what went wrong and how to prevent similar tragedies.

Several veterans' groups and individuals have also come forward to call for action, including Vets Canada and Wounded Warriors Canada.

Veterans' advocate Peter Stoffer said Thursday there are several questions the inquiry will need to address.

The former Nova Scotia NDP MP said the inquiry will need to examine Desmond's transition from military to civilian life, including gaps in services provided by Veterans Affairs Canada and the province.

"The number one recommendation would be that nobody leaves the military or for that matter the RCMP until all support systems are in place," he said. "The services need to be in place before the uniform comes off."

Stoffer added that the inquiry must be open and inclusive.

"It should have access to all the information that it asks for in order to determine, if it's possible, what happened and where lessons can be learned so that this tragedy will not happen again," he said. "I'm just hoping at the end of the day the inquiry will provide some of the answers the family is asking for to give them some comfort and most importantly give them some closure."

More than 130 serving military personnel have taken their own lives since 2010, according to National Defence.

In October, Ottawa promised to improve support for military personnel through a new suicide prevention strategy, which focuses on easing the transition from a military career to civilian life.

With files from Keith Doucette