Indirect object pronoun

Question

In the sentence 'Les amenecé seriamente' I don't understand why the indirect object pronoun 'Les' is used. I would have thought it would have been a direct object pronoun ie 'Los' or 'Las'. Are 'they' not the direct object of the threatening? I seem to often have a problem with this. It's ok when it's a straightforward 'I gave the present TO her' for example where it is quite clear but in sentences like the one above I get very confused as it often seems the indirect object pronoun is used. Any advice greatly appreciated.

Answer

Hola Lydia,
You are absolutely right when you say that "les" is the direct object of the verb amenazar. The reason why we have used "les" here instead of the direct object pronoun "los" is, because with certain verbs (verbos de afección psíquica, e.g. molestar, fastidiar, entretener, amenazar, aterrorizar...) the use of "le/les" instead of "lo/los" is accepted.
In this case both pronouns are accepted, but there are other many cases where this is not accepted, despite being used in parts of Spain. You can read here about "leísmo".
I hope this helps.
Inma