Last Updated Apr 24, 2015 11:20 AM EDT
It now appears American Warren Weinstein and Italian Giovanni Lo Porto, the hostages the White House announced Thursday were accidentally killed in a drone strike, were being used to safeguard an al Qaeda senior leader, CBS News' David Martin reports.
Intelligence analysts never detected any sign of the hostages but did see evidence of a senior al Qaeda operative. That seemed to make it even more unlikely hostages were in the compound since there were no previous cases in which hostages had been held in close proximity to al Qaeda leaders. It now appears the hostages were used as shields for the senior leader, who apparently thought that as long as the hostages were nearby, he was safe from drone strikes.
That leader turned out to be an American named Ahmed Farouq, a longtime al Qaeda operative who once hatched a plot to hijack Pakistani vessels and ram them into American warships.
Several days later, another drone strike killed another American, Adam Gadahn, again without the CIA realizing it.
Gadahn played a leading role in al Qaeda recruiting and propaganda videos. He had been indicted for treason and had a $1 million price on his head.
CBS News senior security contributor Michael Morell said Friday on "CBS This Morning" that it was "very important" to remove them both from the battlefield.
Gadahn grew up on a remote goat farm in Southern California and converted to Islam when he was 17. He attended the Islamic Center of Orange County. Shortly after being kicked out of the center in 1997, Gadahn left the country for Pakistan and joined al Qaeda. His father, Phillip, seemed dumbfounded when he talked to CBS News in 2004.
"I didn't imagine he'd be involved in anything like what they think he might," he said.
President Obama once promised that before the CIA launched a drone strike it would know to a "near-certainty that no innocent civilians would be killed."
"I profoundly regret what happened. On behalf of the United States government, I offer our deepest apologies to the families," Mr. Obama said.
Despite what the president said and hundreds of hours of surveillance of the al Qaeda compound, two very innocent aid workers were killed by a CIA drone strike in January.
"Clearly this calls for a thorough review of what happened," said Sen. Susan Collins, R-Maine.
According to Morell, also a former CIA deputy director, pinpointing the exact location of a hostage can be difficult.
"Hostages tend to be hidden, hidden for days and days and days, so it's quite possible that you might look at a compound for some period of time and not see hostages," Morell said.
The White House spokesman was asked if the president felt any regret for having unknowingly killed two Americans fighting for al Qaeda. He said, in a word, "No."
Morell said if he was in charge of the review, there would be a few questions he'd want answered.
"One is I would want to know whether all the normal procedures were followed here, number one. Number two, I would want to know whether there are any new procedures that we need to put in place. And, number three, I'd want to know how do we do a better job collecting intelligence on what's going on inside these compounds that we're targeting," Morell said.