It's perfectly normal that the Sismi and the Berlusconi government deny any involvement in passing knowingly false intelligence to a foreign allied agency. It would be self-incriminating. I think it would come under anti-constitutional sabotage or the more down-to-earth abuse of office for private interests. Falsifying documents would appear to be a minor offense. Also, I can't see the Niger government issuing international arrest warrants over this.

Italian intelligence officers have been tried and condemned in the past. Francesco Pazienza for abuse of office in the Billygate affair, then again for the Bologna Train Station Massacre along with General Pietro Musumeci and Colonel Giuseppe Belmonte. Others such as General Miceli beat the rap by getting elected to parliament.

In the present case it's going to be very hard to press charges or investigate for that matter. The government immediately opposed state secrecy on the affair when it broke which precluded large areas of investigation.

As for a parliamentary investigation, it will certainly not happen under this government.