I think my son has been scammed

I am writing this as a parent because I need help from the members of Bobae Dream.
I am a parent of a son in his third year of middle school.
Since he was young, my son has been saving his allowance and keeping money in his own account.
He used that money to buy a bicycle two years ago (a fixed-gear bike... it has brakes), and he was an ordinary middle school student who upgraded his bike parts one by one by saving up his own money.
At some point, I noticed him using something called Discord? He would stay up late every Friday and Saturday evening talking to someone.
I still don't really know what Discord is.
The problem starts from here.
My son had 2 million KRW that he had saved since he was young.
He ended up lending that money to someone.
He transferred 500,000 KRW four separate times.
When I asked him who he transferred the money to,
he said he sent it to an older guy he knew.
When I asked what kind of guy he was,
he said he was either running a business or was a manager at a bar.
He said the guy promised to send it back once the shop's accounts were settled, so he sent 500,000 KRW four times.
Since then, whenever my son asked for the money back,
the guy would say, "The settlement isn't done yet, please wait,"
and it has been a month as of today.
I am certain this is a scam,
but my son doesn't think so (I believe he is being gaslighted).
The two of them were still in contact,
and then that guy asked my son for an additional 100,000 KRW, claiming he needed it to settle the accounts, and said he could then send back the 2 million KRW..
That was the moment I realized this was 100% a scam.
It broke my heart to hear my young son say that if he sends the 100,000 KRW, he can get his 2 million KRW principal back.
However, I transferred the 100,000 KRW to my son, and right then and there, my son transferred that 100,000 KRW to that person.
Because there is no difference between a 2 million KRW scam and a 2.1 million KRW scam.
I thought he needed this 100,000 KRW as a lesson for society.
Afterward, my son contacted me saying the settlement still hadn't happened and the money hadn't come in yet.
When I asked him if he finally realized it was a scam
and told him he needs to wake up,
he said he finally understands it's a scam.
Now that I am trying to step in, I honestly don't know what to do.
The person appears to be in his early 20s.
The information my son has is:
Early 20s
Ulsan
Instagram ID
Account number
He says he doesn't know the contact number.
What should I do now?
I ask for advice from the Bobae members.