A verb that means “to prove someone is guilty of a crime”

Preface: I don't think there is a single-word (verb) that expresses the concept I am asking for, in which case I'd settle for the least ambiguous and most common phrase or idiom that describes the following situation.

Context
I was reading a short story from a private student of mine when I came across this line:

Lucy realized she had the proof to frame Robert [for the murders].

To frame someone is to arrange or plant evidence in such a way that an innocent person appears to be guilty in the eyes of the law. My student's sentence would be fine if Robert were innocent of the crime, or if there was no evidence that linked Robert to the murders but somehow Lucy managed to plant false evidence which resulted in his arrest.

But in my student's story, Robert isn't innocent. He did commit the two murders and the evidence Lucy found was not planted, nor false, but led to the police arresting him for the two murders.

I suggested the following solutions:

Lucy realized she found the proof that nailed Robert for the murders
Lucy realized she found the proof to incriminate Robert.
Lucy realized she found the evidence which proved Robert's guilt.
Lucy found the smoking gun that proved Robert's guilt.

Sentences 1 and 2 are fine within the plot of the story but taken out of context, they could still suggest Robert was set up by Lucy, i.e. he was innocent. Sentences 3 and 4 are, I think, the least ambiguous. My student liked the expression “smoking gun” but added:

A smoking gun is not a verb, I still have to say Lucy found the smoking gun which incriminated Robert.

Questions

If “to frame” someone is to plant evidence that ‘proves’ an innocent person is guilty, is there a verb that means: to find evidence that unequivocally proves a person is guilty? Perhaps there is an obscure legal term hidden in OED, or maybe an obsolete expression, which escapes me. Here is my student's sentence with the blank space.

Lucy realized she had the proof to _________ Robert

But I am open to other suggestions and solutions so long as its clear that the evidence shows us that Robert is guilty.

Am I right to ascertain sentences 1 and 2 are possibly ambiguous? And finally, are there other alternatives to the ones I suggested?

Solution 1:

You already have the most common phrase: the evidence to prove [ or that would prove] Robert guilty.

If the word proof is important, simply the proof that Robert was guilty would work well.

Solution 2:

According to Merriam-Webster:

implicate: (3a) to bring into intimate or incriminating connection
evidence that implicates him in the bombing

So I would write this:

Lucy realized she found the proof that implicated Robert in the murders.

You can omit "in the murders" if it is implied by context.

Solution 3:

Convict is the correct word here. It's the strongest and most succinct, though legally speaking, Lucy would not do the convicting: that would be filled by the role of judge, jury, or relevant prosecuting attorney for the government.

Indict and implicate are too weak: especially in modern, western legal systems, the accused benefits from the presumption of innocence. If you have enough evidence to implicate someone, that might mean you have a strong hunch based on a rumor you heard. If you have enough evidence to indict someone, well, now you've got a thumbprint, a motive, and maybe some supporting evidence ... but generally you don't need proof for that. If the evidence is strong enough, then the proof may be sufficient to convict.

Note, the word convict has at least 3 meanings: The word above is a verb, with the emphasis on the last syllable, the "vict". When the emphasis is on the first syllable, "con", it refers to a person who has been convicted of a crime and has not yet finished service their punishment. An "ex-convict" is someone who has served their punishment. Finally, the verb is turned into an adjective via its past participle where one usage takes on a slightly different meaning: "John felt convicted" means (in a way) that "John felt certain and resolute", but possibly with a feeling of guilt and remorse; presumably, this sense of the word comes from the idea that John's conscience convicted John as if he had done a crime; his conviction is now a determination to set thing straight.

Solution 4:

Lucy realized she finally had enough evidence to indict Robert on the charge of murder.

Indict in·dict /inˈdīt/ verb, North American –Google
past tense: indicted; past participle: indicted

formally accuse of or charge with a serious crime.

Because of double jeopardy, one had best be sure you have all your ducks in a row before you indict a suspect. Prosecutors may spend years collecting evidence before they are willing to bring up charges.

Due to the maximum length of time one can be held without charges, suspects of crimes committed (other than those where they're caught red handed), are not placed under arrest until a case is built against them. E.g., Drew Peterson.

You only indict someone once (you think, and the DA agrees that) you have enough ["evidence that ‘proves’ them guilty"] beyond reasonable doubt. This evidence must also include a means of probable cause for said indictment.

However, to find evidence that unequivocally proves a person is guilty, is most likely to be done during discovery (assuming the detective's findings were unsubstantial).

Under the law of the United States, civil discovery is wide-ranging and can involve any material which is "reasonably calculated to lead to admissible evidence." –Wiki

Not even half way through discovery, Lucy realized she already had enough evidence to also indict Robert on the charge of murder.

In the US, all suspects are innocent until proven guilty in a court of law. The colloquial saying you're looking for is 'a smoking gun', however legally the concept does not exist and therefore any word you find is inadmissible.

See also, dead-bang. –definitions.uslegal.com

A dead-bang winner is defined as “an issue which was obvious from the trial record and would have resulted in a reversal on appeal.” James v. McKee, 2009 U.S. Dist. LEXIS 102380 ( E.D. Mich. Nov. 3, 2009)

Take your shot Funboy. You got me dead-bang. –The Crow

And with this new evidence, Lucy realized she had Robert dead-bang.

Solution 5:

I agree that the verb convict pretty much means found someone is guilty of a crime. The proving part is the prosecution process itself.

If you are looking for a more direct way to apply the proof in your sample sentence, I would use committed:

Lucy realized she had proof that Robert committed the murders.