Sorry about what happened to you. This really hurts so much even for me to see someone loose their hard earned money.
I tried to do some small digging as to what may have led to you loosing all you coins and the fact is that BTC D wallet you download was the malware:
According to the wallet name you said you found in your download folder (Electrum-BCD-3.1.2-portable.exe). You definitely downloaded a Fake Electrum BCD wallet.
Genuine BCD wallet App - Electrum-BCD-3.0.5.3-Windows-X86-64-portable.exe
Fake/Hacker's BCD Wallet App - Electrum-BCD-3.1.2-portable.exe
It's now clear that you downloaded the app from the hacker's website; https://www.electrumdiamond.org/ instead of downloading from the official website of Bitcoin Diamond; https://www.bitcoindiamond.org/ [http://btcd.io]
Fake Bitcoin diamond's Certificate has even expired since 12/6/2018
I also noted that the Github user ElectrumBTCD from whom you downloaded the wallet file joined Github only 22 days ago and has only one repository. This is a complete redflag
Finally i decided to scan the said wallet on virus total;
https://www.virustotal.com/#/file/2d91fc6e2102ff0464ba43a1a956ed7854cb45cac8a18c354a8346f71a68dd6d/detection
My conclusion is this is the malware that got you funds stolen, whoever is behind it has your funds. Am not so technical in tracing people using ip addresses so i will just leave these here in hope that the info might help someone who is able to track back to the evil hacker or hackers.
I tried to do some small digging as to what may have led to you loosing all you coins and the fact is that BTC D wallet you download was the malware:
According to the wallet name you said you found in your download folder (Electrum-BCD-3.1.2-portable.exe). You definitely downloaded a Fake Electrum BCD wallet.
Genuine BCD wallet App - Electrum-BCD-3.0.5.3-Windows-X86-64-portable.exe
Fake/Hacker's BCD Wallet App - Electrum-BCD-3.1.2-portable.exe
It's now clear that you downloaded the app from the hacker's website; https://www.electrumdiamond.org/ instead of downloading from the official website of Bitcoin Diamond; https://www.bitcoindiamond.org/ [http://btcd.io]
Fake Bitcoin diamond's Certificate has even expired since 12/6/2018
I also noted that the Github user ElectrumBTCD from whom you downloaded the wallet file joined Github only 22 days ago and has only one repository. This is a complete redflag
Finally i decided to scan the said wallet on virus total;
https://www.virustotal.com/#/file/2d91fc6e2102ff0464ba43a1a956ed7854cb45cac8a18c354a8346f71a68dd6d/detection
My conclusion is this is the malware that got you funds stolen, whoever is behind it has your funds. Am not so technical in tracing people using ip addresses so i will just leave these here in hope that the info might help someone who is able to track back to the evil hacker or hackers.