Dictionaries say that blame is a transitive verb. Even though we already have the phrase be to blame for something, can we use the following sentence?
Officials believe that more than one person may be to be blamed for the fire.
Dictionaries say that blame is a transitive verb. Even though we already have the phrase be to blame for something, can we use the following sentence?
Officials believe that more than one person may be to be blamed for the fire.
There are two different questions in this post.
Longman Dictionary of Contemporary English: For Advanced Learners provides the example on p159:
"Officials believe that more than one person may be to blame for the fire." [emphasis mine]
"be blamed" is a valid phrase:
"Moreover, you must remember that the beauty I possess was no choice of mine, for, be it what it may, Heaven of its bounty gave it me without my asking or choosing it; and as the viper, though it kills with it, does not deserve to be blamed for the poison it carries, as it is a gift of nature, neither do I deserve reproach for being beautiful; for beauty in a modest woman is like fire at a distance or a sharp sword; the one does not burn, the other does not cut, those who do not come too near." -- Don Quixote by Cervantes, Miguel (Free Library) [emphasis mine]
As the possible application of the phrase be blamed in the example sentence is in question, we may say:
"Officials believe that more than one person may be liable to be blamed for the fire."
which seems a grammatically valid sentence.
I think other answers and comments are splitting hairs over a potential distinction which appears to be supported by the way we use may be and to be blamed. But there's no logical, semantic, or grammatical justification for claiming the redundant/clumsy inclusion of "to be" means anything (apart from suggesting that perhaps the writer may have been careless).
Consider...
A: Because he may have traveled abroad himself, he knows how difficult it may be to be understood in a foreign language.
B: In some cases, an individual's goal may be to be perceived as a good citizen.
Only one meaning is possible, and short of a radical rewrite it's difficult to avoid the repetition of "be". So we accept this, because it's not that clumsy.
In OP's example, we can separate the clashing components (along with other trivial adjustments)...
Officials believe it may be that more than one person is to be blamed for the fire.
...or we can make a slightly greater adjustment...
Officials believe that perhaps more than one person is to be blamed for the fire.
But the most trivial change is to simply drop "to be"...
Officials believe that more than one person may be blamed for the fire.
In all cases, there's ambiguity as to whether may be/perhaps attaches uncertainty to the matter of whether there are one or more arsonists, or whether the arsonist[s] will in fact be blamed/charged. Stylistically it would be pretty awful, but you could express both senses simultaneously with...
Officials believe that maybe more than one person may be blamed for the fire.
It is in fact possible, but almost certainly not what was intended. I'm to be married today is a way of saying 'I will be' or 'I expect to be'. So more than one person is to be blamed for the fire means We intend to blame several people for this, implicitly ...no matter who was actually at fault. Possibly true, but not what a spokesman is supposed to say: it may of course be a Freudian slip.
Edit: The passive is the usual construction in this situation, which is probably what confused the spokesman; unfortunately (whether to be married or to be blamed)it is more a prediction than anything else, which is what I object to. The phrase meaning 'responsible' is specifically to blame. Fowler calls it "an illogicality long established as idiomatic"; I would say it is just as well-constructed as the synonym at fault.