The "someone they trusted," thing has always bothered me. Because what Boetcher actually said is that they "believe" the girls left with some one they trusted. Although it seems straight forward on it's face, its actually a very vague statement. The word believe can mean a number of different things here.
1) They "believe" the girls left with someone they trusted simply because they think it's the most likely scenario and can't otherwise explain how someone could abduct multiple people at once. The word "believe" here could just as well be "speculate"
2) It could also mean that they'd identified the person seen talking to the girls at the mall and knew for a fact the person was someone they trusted, but didn't know if the girls left with this individual because no one saw that happen. Hence the qualifier, "believe."
3) It could mean they have a credible tip, and they "believe" it's true, but no proof.
4) It could also mean they had a suspect in mind and the suspect was someone the girls trusted. Therefore they "believe" the girls left with this person even that there's actually nothing to back it up. Let's hope that's not the case, if it is, there may have been some concrete tips ignored because it wasn't in line with the suspect they have in mind.
The other interesting thing about the "believe the girls left with someone they trusted," statement is that it was made over 25 years after the disappearance and at that time they also said they were focusing on as many as 5 different suspects. This tells me that whatever they had, it wasn't much. Therefore I tend to discount the statement all together. Maybe they left with someone they trusted, maybe they didn't, all we know is the police "believed" they did at one time. This is one of the reasons I'd love to see the police files.
I like solid word choices. As it is, this statement leaves a lot up for interpretation.