Locked file is stuck in trash
The group is showing as restricted - this may indicate that it's due to SIP.

Try: https://stackoverflow.com/questions/30768087/restricted-folder-files-in-os-x-el-capitan tells you how to temporarily disable SIP to delete the file.

Could also try sudo chown [owner]:[group]? (Although if it is SIP, I don't think that it's this easy to get around).