The prosecutor's office said in a statement that Giordano is "suspected of involvement in the possible drowning" of Gardner, whose body has not been found.
Prosecutors "have not been required to pinpoint whether we will eventually charge murder or manslaughter, but that will come at a very much later date," Stein said in a telephone interview.
Without yet recovering a body, "kidnapping has crossed our mind as a working hypothesis, but there's no way we could corroborate that, so that working hypothesis has been dropped," he said.
Stein says prosecutors asked Giordano to voluntarily provide a DNA sample. But he acknowledges prosecutors have not found any clothing or articles belonging to Gardner directly related to the possible killing.
"It's needed for somewhere down the road, regardless of the charge," Stein said of the sample.
Stein said Giordano declined to provide the sample voluntarily. Prosecutors asked the judge to order the sample, and the request was granted.
Giordano's next court appearance will be in 16 days, and Stein anticipates asking the magistrate to allow Giordano to be detained another 60 days.
"After that, he will likely be charged," says Stein.
Stein said Giordano's "statements do not comply with the information we have developed. We continue to have serious doubts about his story."
