Tammy's guy said he saw the girls at 2:30 according to this transcript.
http://edition.cnn.com/TRANSCRIPTS/1207/16/ijvm.01.html
Snipped
And one man stepped forward and said, "Yes, I seen them going east on the bike trail at about 2:30."
So...we have a jogger who saw the bikes ALONE at 2:00 and we have another person who Tammy spoke with who saw the girls riding the trail at approx 30 mins later.
So...maybe the girls were there the entire time from the time they were seen on CCTV.
Mr. Gamerdinger said he saw bikes and no girls at his sighting...then again at 2, a jogger claims HE saw the bikes and no girls...and then at 2:30 this witness Tammy spoke with claims to have seen the girls.
OK...gonna throw this out there as yet ANOTHER possible scenario to chew on. Where could the 2 girls have been at the lake that wasn't out in the open for someone to be "hanging" with them?
Bathroom? Wooded area? Pavilion? Went for a ride in a vehicle for a bit?
Maybe the girls weren't even abducted and gone until later on in the afternoon. It is fully possible for the family to have driven by the lake and not seen the girls.
So...let's ASSUME that the girls were there at 2:30 and this witness was correct.
Now what theories open up?
ETA: Tammy states she was there at a quarter to 3.
"and this was at about a quarter to 3 -- and keep in mind the last they were seen was at 11:30 a.m., when they told mom they were going on the bike ride. So that is the last time they were for sure seen. And now, it`s going on to -- it`s getting close to being a quarter to 3."
So even from the time that the witness claims he saw them riding...Tammy and crew were there at approx 2:45ish so again, within 15 mins they aren't there...but 15 mins opens up enough time for someone to abduct someone and be gone.