A man suspected of killing his mother and brother in separate family violence shootings was the head of the local sporting shooters branch.

The 58-year-old man is under police guard in hospital following the deaths of his 82-year-old mother in Red Cliffs near Mildura in Victoria and 63-year-old brother at Rufus in New South Wales on Tuesday.

In a statement posted on Facebook, the Sporting Shooters’ Association of Australia (SSAA) Victorian branch identified the alleged gunman as Paul Cohrs, the president of SSA Mildura.

“We are deeply shocked and saddened by this news and our thoughts are with the Cohrs family.”

The group later clarified the comment, saying the double fatality would “undoubtedly become an anti-gun issue” and it had made a public comment because “we do not want to allow anti-gun groups and the media to control the narrative that will come from this tragedy”.

Victorian police said they discovered an elderly woman, reported to be 82-year-old Bette Schultz, shot dead in her home at Red Cliffs, on the southern side of the Murray river, at 12.30pm Tuesday.

A four-year-old boy, who was also at the house, was unharmed and taken away from the house by police before a crime scene was declared. Police say the boy was related to Schultz but it’s unclear whether he saw the shooting.

An hour later and 125km away, NSW police were called to a second shooting at Rufus, near Lake Victoria on the northern bank of the river, where the body of the 63-year-old man, reported to be Ray Cohrs, was discovered, along with a 55-year-old man who was uninjured but held against his will.

The alleged shooter was discovered nearby, critically injured with what appeared to be self-inflicted gunshot wounds.

Detectives on both sides of the border are investigating the incident and so far no charges have been laid.

Fairfax Media has reported that the victims were Paul Cohrs’s mother and brother, but police would not confirm the relationship except to say that “all parties are believed to be known to each other”.

In a statement, NSW police said it was a “suspected domestic violence-related shooting”.

It is the sixth suspected domestic violence killing involving the death of a woman this month, according to the Counting Dead Women project by Destroy The Joint.

Police have said they are not looking for anyone else in connection to the shooting but have asked anyone with information to contact Crime Stoppers on 1800 333 000.

• Crisis support services can be reached 24 hours a day: Lifeline 13 11 14; Suicide Call Back Service 1300 659 467; Kids Helpline 1800 55 1800; MensLine Australia 1300 78 99 78; Beyond Blue 1300 22 4636. If you or someone you know is impacted by domestic or family violence, call 1800RESPECT on 1800 737 732 or visit 1800RESPECT.org.au