A witness who knew Sydney siege gunman Man Haron Monis in Iran says he believed Monis worked for the Iranian intelligence service.

The man, whose name is suppressed to protect his identity, told the inquest into the Sydney siege Monis once intimidated a security guard at a Tehran private hospital just by showing an identity card.

The witness had worked as an accountant for Monis in Iran in the 1990s, setting up companies through which Monis made a lot of money on-selling goods including truck tyres that he obtained from the Iranian government, the inquest heard.

On Friday, the man, who now lives in Australia after fleeing Iran in 2000, told the inquest of a time when he dislocated his shoulder and went to a public hospital in Tehran.

Monis – who then went by the name Mohammad Hassan Manteghi – disapproved of the public hospital. Monis took him instead to a new, private hospital for “very, very wealthy” people where a security guard stopped them because they had arrived by taxi – not the usual transport of the facility’s rich clients.

The man said he saw Monis show an ID card to the guard, who immediately let them in.

“He looked a little scared,” the man said.

Mysterious and bizarre details of Monis’s early life were revealed by the man, who said Monis once asked him to carry 12,000 deutschmarks out of Iran on a holiday to Malaysia.

Previous witnesses have told of Monis’s paranoid behaviour in Australia, where he believed he was under constant surveillance.

The man on Friday said Monis showed the same “fussy” and paranoid behaviour in Iran. Monis hated people touching personal items in his office and would not dry his hands on his towel in the bathroom, instead standing and waiting for his hands to dry in the air, the man said.

He spoke in whispers and was constantly looking around, checking behind taxis to see if he was being followed, the inquest heard.

Monis fled Iran to Australia in 1996.

The witness said he met Monis again in Australia and observed a change in him around 2007, when he began voicing extreme religious views and describing western culture as no friend of Islam.

But the witness said he thought Monis used religion simply as another way to seek attention, and Monis later abandoned his extremist language.