Correction, they have declared a suspect, himself.
The correlation between what they have and what they say is unknown at this point. It could be that that's exactly what they have. It could be that it's what they want to have. And it could be that it's what they want a potential suspect to think they have.
At this point in the game, all we know is what they're saying. What they're thinking may or may not be related.
It's also important to note that police forces have finite resources. If they think any likely suspect would be prohibitively expensive to prosecute, or is likely to get off for some reason, they're likely to put resources into cases where they can get a result. For example, in England, rape cases are notoriously difficult to prosecute, so something like 90% of cases are never investigated and most kits for obtaining perp DNA are never tested.
And, finally, it's important to remember that police forces are not filled with geniuses. In England, the Yorkshire Ripper called the police and confessed, but wasn't even added as a suspect for a year or two after that. And a number of gay men suddenly dropping dead in Scotland was chalked up to accidental overdose until a survivor reported that someone had tried to murder him. And even then, it took time for the police to take him seriously.
These are important. Most things attributed to malice are actually all about stupidity or capability.
The truth is, we'll never know the actual truth. Because governments and corporations are grotesquely incompetent, we may learn some of it eventually, but there'll be so much static that knowing what's signal will be impossible anyway.