Police have arrested a fourth suspect following the shooting at a farm in Back Lane, Aughton, near Ormskirk on July 28.
Armed officers swooped on the farm after receiving an 999 call reporting an armed robbery in progress at around 9.40pm.
A gang of people wearing balaclavas and wielding firearms had raided the farm in the sleepy, tree-lined village.
But the gang had managed to escape before police arrived.
Officers found a 65-year-old man suffering from gunshots to his ankle and knee. He was rushed to hospital where he underwent emergency leg surgery. He continues his recovery, but police said he has suffered life-changing injuries.
Four shotguns and ammunition belonging to the farmer, as well as jewellery, watches and cash were stolen from inside the property during the raid.
A total of four people have now been arrested, including a 56-year-old man from Ormskirk who was detained on Wednesday (September 11) on suspicion of robbery.
He has since been bailed pending further enquiries.
In the weeks that followed the armed robbery, police made a number of arrests.
A 30-year-old man from Liverpool was arrested on suspicion of armed robbery and has been released under investigation pending further enquiries.
A 37-year-old woman from Liverpool was arrested on suspicion of aggravated burglary, possession of firearms offences and fraud. She has been released under investigation pending further enquiries.
A 38-year-old man from Kirby was arrested on suspicion of robbery, possession of a firearm whilst committing an offence and fraud by false representation. He has been bailed pending further enquiries.
The investigation is ongoing and detectives are appealing to the public for any information that might help them identify those involved in the raid.
Det Insp Jason Richardson of Lancashire Police, said: "This was an extremely serious incident where a 65-year-old man has suffered life changing injuries and our thoughts remain with him at this difficult time.
"A woman who was also present when the robbery took place has understandably been left traumatised by her ordeal.
"While we have made four arrests, our enquiries are ongoing.
"We know some time has now passed since the incident but that won’t stop us from moving forward with our investigation and we have a dedicated team of detectives committed to the enquiry.
"I would urge people to cast their minds back to that date and think if they heard or saw anything suspicious.
"If you haven’t already contacted us and have any information, no matter how small or insignificant, we would like to hear from you."
Anyone with information about the incident or the location of the people involved is asked to call Lancashire Police immediately on 101 quoting incident reference 1553 of July 28.
Alternatively independent charity Crimestoppers can be contacted anonymously on 0800 555 111 or online at crimestoppers-uk.org.