Mumbai terror suspect was DEA informant

One June day in 1988, customs agents at the Frankfurt, Germany, airport pulled aside an intense and striking young man waiting to get on a plane back home to Philadelphia. They suspected he had heroin in his suitcase. They were right -- two kilos' worth from Pakistan, hidden under a false bottom. He wasn't tough to crack: Before the day was out, Daood "David" Gilani decided to save his own skin, agreeing to betray his drug-dealing partners by helping U.S. drug agents set up a sting. It was the beginning of a complicated, off-and-on relationship as a confidential informant with the Drug Enforcement Administration -- one that lasted more than a decade.