Decem testes idem dicunt: servum innocentem esse et nihil cepisse.

Here idem means the same thing. It is the object of dicunt.

A learner might expect something like iidem, but that would mean the same people/men as a nominative plural. Here the sense is not the same witnesses say..., but the witnesses say the same thing. So idem is neuter singular: the same thing.

The colon introduces the content of what the witnesses are saying. In other words, everything after the colon is the statement being reported.

It is also worth knowing that punctuation in printed Latin is editorial. Ancient Latin was not originally written with modern punctuation, so the colon is there to help the reader see the structure.

Because after a verb of saying like dicunt, Latin often uses an indirect statement construction: accusative + infinitive.

So:

• servum = the subject of the indirect statement, put in the accusative
• innocentem esse = to be innocent
• together: servum innocentem esse = that the slave is innocent

This is very different from English, but it is one of the most important Latin constructions to learn.

Because this is an indirect statement, not a direct statement.

• Direct statement: servus innocens est
• Indirect statement after dicunt: servum innocentem esse

Latin changes the finite verb (est) into an infinitive (esse) when reporting what someone says, thinks, hears, knows, and so on.

Because innocentem agrees with servum, and servum is accusative in the indirect statement.

In a direct statement you would say:

• servus innocens est

But in indirect statement both the subject and its predicate adjective shift into the accusative:

• servum innocentem esse

So innocentem is accusative singular masculine, agreeing with servum.

Because cepisse is the perfect infinitive, while capere is the present infinitive.

The verb is capio, capere, cepi, captum. Its perfect stem is cep-, so the perfect infinitive is cepisse.

In indirect statement, the perfect infinitive usually shows action earlier than the main verb. So dicunt ... nihil cepisse means they say that he did not take or has not taken anything.

If Latin used capere instead, the sense would be more like that he is taking or that he takes.

The subject is still servum.

Latin often gives one accusative subject and then lets it apply to more than one infinitive:

• servum innocentem esse
• et nihil cepisse

So the full sense is that the slave is innocent and that the slave took nothing, even though Latin does not repeat servum.

Nihil means nothing, and here it is the object of cepisse.

So nihil cepisse means to have taken nothing.

A useful point: nihil is a very common neuter pronoun, and it often functions like an accusative object without needing a separate noun.

The direct statement would be:

Servus innocens est et nihil cepit.

Then after dicunt, Latin converts that into indirect statement:

servum innocentem esse et nihil cepisse

This is a very helpful way to understand the grammar: first imagine the direct statement, then see how Latin transforms it.

Yes, but it is also very normal Latin.

Latin word order is more flexible than English. This sentence first gives the main clause:

Decem testes idem dicunt

and then gives the reported content:

servum innocentem esse et nihil cepisse

Within the indirect statement, servum comes first to establish who the statement is about, and then the two infinitive phrases follow. English cannot copy the order mechanically, so it is better to follow the grammar than the exact sequence of words.