Jill Brookes, 62, was discovered lying in a pool of blood at her second-hand book store in Altona’s Harrington Square following a savage robbery on July 20 last year, but so far no arrests have been made.

Jill’s husband Michael Overend said the beating had left his wife with severe brain damage. “She has no skull on the left so she needs to wear a helmet,” he told reporters on Thursday.

Mr Overend said Jill’s injuries were localised to the left side of her head, meaning she could understand conversations and recognise faces but was unable to communicate properly.

“I will never have my wife back. She will never come home,” he said.

“I had expected us to retire and live the rest of our lives together… that’s just not going to happen now.”

He said it was unlikely his wife would recover beyond her current condition, but if her attacker was brought it justice it would bring him “some peace”.

“I’m angry, but no one in their right mind could do what was done to my wife,” he said.“They probably need just as much help as Jillian does.”

Police believe the author of a mysterious note could hold vital information about the attack. The note, crafted with cut-out newspaper letters, was anonymously dropped into the Altona North police station in May.

Detective Senior Constable Matt Noonan would not disclose the contents of the letter, but said investigators believed the note to be legitimate because it contained “fairly specific” information about the incident.

Describing the attack as ‘‘callous’’, Senior Constable Noonan urged anyone with information, including the author of the letter, to come forward.

“This has been an incredibly challenging time for Jill and her family,” he said.

“We’ve been working hard over the past 12 months to try and identify who is responsible and bring about some justice for the Brookes family.

“The important thing is that if you know something then say something. It might seem like a small or insignificant detail but it could make a big difference in this case.”

Investigators have previously released details of a man who they believe could assist with their inquiries, along with information regarding a truck seen in the area around the time of the assault.

The man was described as Caucasian and of a medium build. It is believed he was wearing full khaki overalls and a dark, check flannel shirt at the time of the incident.

Anyone who may have information is asked to contact Crime Stoppers on 1800 333 000 or visit www.crimestoppers.com.au.