The attackers who killed nearly 180 people last week in Mumbai, India, had help from a Bangladeshi national, Indian security sources told CNN sister network CNN-IBN Thursday.
The Bangladeshi national bought cell phone SIM cards for the attackers at several locations inside India, the sources said.
SIM cards - subscriber identity modules - are portable memory-chips that make it easy to switch cellphones. Intelligence experts say they're used by terrorists to throw their pursuers off the trail, CNN reported.
Indian authorities believe all the attackers were Pakistanis, specifically blaming Laskar-e-Tayyiba (LeT), an Islamic militant group based in Pakistan. LeT has denied any responsibility for the attacks, but the sole surviving gunmen told interrogators he was trained by LeT, Indian authorities have said.