Brisbanites are being urged to keep an eye out for missing man Omar Fattal who hasn't been seen for more than week and may be disoriented.
The 70-year-old was last spotted on CCTV footage walking into the bus-only area of Woollongabba Bus Interchange about noon on May 26.
Senior Sergeant Kyle Doyle says Mr Fattal left his home at Mount Gravatt East about 8.30am before he was being spotted about 9am at Garden City Bus Interchange.
She says Mr Fattal is an active member of the community and worshipper at the Holland Park Mosque.
"He's very local to this area, he's not savvy on public transport, and it's very out of character for him not to come home within about an hour of going walking or going for prayers at the Mosque," Sgt Doyle told reporters.
Police have followed up on several sightings of Mr Fattal, including one that led to another missing person being found.
His bank accounts haven't been touched since he disappeared and his mobile phone was last traced to the Corinda area in the city's west.
Sgt Doyle said there's still no clear indication of why Mr Fattal suddenly disappeared but they believe he may have been disorientated.
Fouad Fattal said his father, who has early stage dementia, had never gone missing before and catching up to two buses in one day was out of character.
"We're obviously quite concerned for his wellbeing and just wish that he comes home, you know, or at least informs us that he's ok, you know what I mean, that's all we're pleading," Fouad said.
"Not to have an understanding of where your father is or a loved one is absolutely horrible and, you know, you can't focus on anything, you can't do anything," Fouad said.
Imam Uzair Akbar said Mr Fattal usually attended three of the five daily prayers at Holland Park Mosque
He said initially they thought he had not shown up due to a cold or flu, but to hear Mr Fattal has disappeared was very disturbing.
"Yes, we're praying daily for him," Imam Uzair said.
"We have used all our platforms to spread out the message, so most probably all the Muslims in Brisbane by now know that Omar is missing."
Sgt Doyle urged the public to keep an eye out for the 70-year-old and to contact police if they see him.