"There are officially four people arrested, but the process remains ongoing," Deputy Interior Minister Mahmud Aleuy said on local channel Canal 13.
The suspects were arrested in different spots in the capital, including one who was detained while trying spend some of the ill-gotten funds at a mall. He was carrying a suitcase with USD 120,000.
In the August 12 robbery -- which unfolded over just a few minutes without a single shot being fired -- eight masked gunmen, disguised as airport employees, stole more than USD 7 million from an armored car belonging to US security firm Brink's on a runway at Santiago's airport.
The thieves fled aboard two vans, one of which they abandoned and set ablaze about three kilometers (1.8 miles) from the airport.
It was the second major Chilean heist to hit Brink's in recent years.
The company was also the target of what was previously the largest robbery in the country's history, the 2006 theft of 922 million pesos, then worth about USD 1.7 million, at the same airport terminal.
