Gary Giordano and Robyn Gardner
Elton Malone/AP; Natalee Holloway Resource Center/AP
08/22/2011 AT 09:30 AM EDT
While Gary Giordano has told police that traveling companion Robyn Gardner disappeared
in Aruba after the two had gone snorkeling, a fisherman who saw them contradicts Giordano's claim
The witness says the couple took a walk along the reef at 4 p.m. and then drove away a short time later without going into the water, reports ABC News
"We're investigating that material, seeing the relevance to the investigation," said Aruba Solicitor General Taco Stein.
Last week, Giordano, 50, was ordered to remain
in an Aruban jail for another 16 days while police investigate what they call "serious inconsistencies" in his story about the Aug. 2 disappearance of Gardner, 35. Police on the Caribbean island presume the Maryland woman is dead.
The search for Gardner resumes on Monday. The FBI is also looking into a $1.5 million American Express accidental life insurance policy
taken out on her, naming Giordano as the beneficiary.
Over the weekend, FBI agents reportedly searched Giordano's Maryland home, seizing cell phones and laptops.
Aruba Police have requested that members of the public with possible information about Gardner's disappearance call 011-297-582-0695. The American tip line for the Natalee Holloway Resource Center
, which is assisting with the case, is 407-237-2295.