Portugese Legal System?

Why does everyone write off the Portugese. They do proper investigations they don't let anything slip in case they frame the wrong person, they wait till all their paperwork is in place, they wait till all the results are in. Not like us we pull in a suspect, tell everyone what we've done, leak it to the press so most suspects get off because they can't get a fair trial, or delay the courts and put in the wrong evidence so the case gets thrown on a technicality. Why penalise a police force that refuses to make any judgements until they are 100% strong in their evidence. They may have taken a long time but they have been speaking and involving New Scotland Yard and some of the most extensive DNA testers in the world.