The other robbers escaped in a silver-coloured Audi which they abandoned for another vehicle, police said. Both cars were found on Friday and police took three people into custody on Friday evening on suspicion on being involved in the robbery.
The 26 year-old who was shot is still in hospital care, and their condition is being described as "very critical".
"We do not want to comment on where we arrested them, but can confirm that we have arrested and taken three people into custody", said Lars Byström from the Stockholm police on Friday evening. He said police would continue to look for other people suspected of being involved in the robbery on Friday morning.
A fourth suspect was taken into custody later on in the night on Friday. On Saturday afternoon police took yet another person ino custody for questioning, writes newspaper Svenska Dagbladet. In total, five people suspected of being involved in the robbery are now in police custody, and one is in hospital.
Nyström said on Saturday that police may arrest more people as they investigate further.
"It is very possible that more people may be arrested. We have many witnesses and four people in custody, so from the point of view of the investigation, things are looking good," Byström said.
Four masked men reportedly robbed the jewelry store, with one remaining in the escape car while the others smashed a jewelry counter inside the shop, witnesses said.
The alarm came in at 11:30 AM. By lunchtime, there had been no arrests.
"I saw two guys inside the jewelry store. I was in an escalator, 10 or 15 metres away and heard people screaming," one witness told news agency TT.
"It was brutal. Lots of people are very upset. I went into a shoe store which took its window bars down. Several people were shocked and in tears."