It's a question that arose after Wednesday's release of search warrants issued two days after his March 3 arraignment in the Chelsea King murder case. The court documents, sealed for the past month, indicate that stalking may have been part of Gardner's modus operandi.
Six and a half weeks after Amber went missing, according to court records, a young woman, possibly 20, flagged down an Escondido police officer to complain about a "gray vehicle" whose driver "had been following her all day for no reason."
The officer pulled him over and identified him as Gardner, but the woman had left the area before a crime report could be taken.
Could that report have led authorities to Gardne's criminal background?
"They're not idiots," Carlos said, referring to the police. "I mean, if you have a report of a sex offender stalking somebody, they're going to do something about it.... It's not a matter of being overworked. They would recognize that as being a sign of trouble, a sign of somebody who was acting out -- and do something about it."
Also included in the search warrants released Wednesday was a declaration by a sheriff's detective that noted that a witness who saw Amber walking to Escondido High School on Feb. 13, 2009, the day she disappeared, was "in the company of a tall, 'doughy' male."
Gardner stands 6 feet 2 inches tall and weighs 230 pounds.
"He probably didn't whack her in the head in the middle of a residential area," said Marc Carlos, a San Diego defense attorney who has represented dozens of sex offenders. "He most likely talked her into a situation where she got in the car with him -- or at least left the area with him."
The four warrants also named nearly three dozen telephone service providers, seeking records of calls made from and to six numbers used by Gardner between August 2007 and last February. No evidence was turned up, however.
One of the six phones Gardner used, identified in the search warrants, belonged to an El Cajon firm that employed him as an electrician for more than two years, until layoffs last October.
A company official described Gardner a a hard woker, well-liked and said that nobody there was aware he was a registered sex offender.