I'm afraid to say that merely because people were seen in the vicinity of the apartment, does not make them suspects.
and by the way who saw these blond men ?
and how many apartments overlooked each other ?
Do you really think that people looking at another building constitutes direct evidence of abduction ?
If you do, the expression clutching at straws doesn't even come close.
I would have thought that witnesses who had noticed something they took the bother to inform the police about might be considered with a bit more respect than they have been.
Quite often in child abduction cases, the only evidence is eye witness testimony.
Don't tell me an expert such as yourself is unaware of the sisters Jayne Jensen and Annie Wiltshire?
**snip
Although the two sisters contacted Portuguese police within hours of Madeleine's disappearance, their evidence was ignored for six months.
The women met police three times within 24 hours, tried to find out who the strangers were themselves and made several follow-up phone calls to the authorities.
But it was not until six weeks ago that a formal statement was finally taken.
The two women, both divorcees from Maidstone, Kent, spent 11 hours with British police officers providing details of their evidence and later met private detectives from Metodo 3, the agency employed by the McCanns to find their daughter.
They intended to remain anonymous but when their names were leaked to a Portuguese newspaper and they found themselves wrongly accused of waiting eight months before coming forward, they decided to reveal the truth.
The sisters said they were immediately struck by the behaviour of the two men on the balcony.
http://www.dailymail.co.uk/news/article-504950/British-witnesses-We-saw-blond-men-balcony-Madeleine-apartment.htmlThere is an interesting synopsis of other witnesses here ...
https://shininginluz.wordpress.com/tag/jayne-jensen/