The Delhi Police investigation in the case will soon unravel everything, he said.
"Jaldhi doodh ka doodh, paani ka paani ho jayega (Soon everything will be clear). No guilty person would be spared and strictest punishment would be given to them," he said.
The Home Minister also did not rule out nexus of middlemen and some government officials in the espionage case and indicated expanding the probe to other Ministries.
"It is possible. I am not ruling out any possibility. Delhi Police investigating the whole issue. I think the issue will come to light very soon," he said replying to a question on involvement of middlemen.
"But it is certain that such things have been going on for a long time and that is why the situation has reached such a stage," he said.
Singh said it is a matter of satisfaction that the espionage case has been unravelled by the NDA government. "If we were not alert, these things would not have come to light," he said.
Five senior executives from top energy firms and two consultants were among those arrested on Friday in the sensational corporate espionage scandal in which classified documents including an input for upcoming Finance Minister's budget speech were allegedly leaked.
A total of 12 people have been so far arrested in the case. The Delhi Police, which is probing the case, reports to the Home Ministry.
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