Suspected ISI operative Major Sameer Ali visited the Karachi control room of the 26/11 attacks when the mayhem engulfed Mumbai and gave several instructions to LeT 'commander' Zaki-ur-Rehman Lakhvi.
This was stated by Syed Zabiuddin Ansari, alias Abu Jundal, during his interrogation by security agencies, official sources said.
Pakistani-American LeT operative David Headley too had given information about Major Sameer's role in the 26/11 attacks.
Another suspected ISI officer Sajid Mir, who was also involved in the Mumbai attacks and conspiracy to carry out other terror acts in India, helped Ajmal Kasab and nine other terrorists involved in the 26/11 strikes, to get training in Baitul Mujahideen.
Mir was a key motivator and organiser of the country's worst terrorist attack, which claimed 166 lives, Jundal told interrogators.
When the Mumbai attack was over, Major Sameer told all those present in the control room to disperse and go underground, the sources said.
While Jundal went back to Baitul Mujahideen, Lakhvi stayed at a protected house with his three wives.
Following international pressure, a few weeks after 26/11, sleuths of Pakistan's Federal Investigation Agency raided the control room and destroyed it, they said.
Months later, when FIA raided Baitul Mujahideen camp, they arrested Lakhvi from there.