It's the unspoken, secret truth that everyone following Apple v. Samsung knows: Boiling barely below the surface, this wide-ranging patent infringement case is really about Google and its dominant Android mobile OS. And this week, for the first time, we find that Google actually offered to help Samsung mount its defense against the litigious Cupertino firm that is bristling as Android steals away its two biggest markets.

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News of Google's behind-the-scenes involvement came courtesy of a recorded witness deposition that Apple played for jurors: In it, Google attorney James Maccoun confirmed that Google and Samsung exchanged email messages in which Google offered to help cover Samsung's legal expenses and possible damages payments, and offered indemnity on some of the patent infringements for which Apple is suing. The emails note that Google is legally entitled to offer this help as part of its "contractual obligations" to Samsung, its biggest hardware partner and the biggest seller of smartphones in the world.

Apple has launched a series of patent infringement lawsuits throughout the world against Samsung, which it accuses of copying its hardware and software designs for the iPhone smartphones and iPad tablets. And although some of these charges are indeed specific to Samsung's designs—like the general look and feel of its hardware devices—many are in fact a proxy campaign against Google because they relate to interfaces found in Android. Apple is suing Samsung because that firm is the one selling the infringing products to customers.

Related: Apple vs. Samsung Heads to Second Jury

The current case is the second in which Apple and Samsung have faced off in court in the United States. In the first, Apple won handily, with a jury determining that Samsung infringed on five Apple patents and awarding Apple over $1 billion in damages. That case concerned older devices, however, and the damages award has since been reduced to $929 million.

This second case raises the stakes because it concerns more recent Samsung products. Apple is seeking $2 billion in damages this time, and as before is seeking an injunction banning certain Samsung products from being sold in this country.

What's not clear is whether Google broadly indemnifies Android licensees that bundle Google apps and services on their devices. Mr. Maccoun thus far has only confirmed a deal between Google and Samsung, and it's possible that Samsung, given its dominant status, was able to obtain better licensing terms than smaller Google partners. Furthermore, some believe that these developments refutes an earlier Samsung statement in which the firm said it had not sought patent indemnification from Google. But Mr. Maccoun clearly stated that Google approached Samsung with the offer.