The police have released a grab from CCTV footage showing Karmenu Fino on the day he went missing from St Vincent de Paul home for the elderly.
The 83-year-old man was wearing a light blue t-shirt and dark pants.
A spokesperson said an intensive search was ongoing.
Two other, more recent photos of the man were also published on Friday.
Earlier, Times of Malta reported CCTV footage shows the elderly casually walking out through the home's main gate at 3am on Wednesday.
Fino does not need a walking aid, according to sources close to the government’s largest home for the elderly.
The CCTV footage is also being analysed by an internal inquiry, being conducted by retired judge Geoffrey Valenzia. It is seeking to establish the facts and made recommendations to prevent similar incidents from taking place in the future.
Sources said the inquiry will also call in the guard on duty that night to find out why he failed to see and stop the old man as he walked through the gate at that time of the morning.
Any information can be passed on to the police at village stations, on 2122 4001 or 119.