A Northern California jury on Monday found that Google Inc infringed upon Oracle's copyrights on the structure of part of the Java software programming language, in a high stakes trial over smartphone technology.
However, the jury failed to decide after days of deliberation whether Google had the right to fair use of that copyrighted structure.
The partial verdict was read in a San Francisco federal courtroom.
Despite finding Google infringed upon some of Oracle's copyrights, the lack of a clear, full decision may represent a setback for Oracle.
The US software company is trying to prove the Internet search leader did not have a right to fair use of Java's structural and organisational elements.
Google's lawyers challenged the key jury decision on Java copyrights after the Monday verdict, moving for a mistrial.
Oracle sued Google in August 2010, saying its Android mobile operating system infringes on its intellectual property rights to the Java programming language.
Google says it does not violate Oracle's patents and that Oracle cannot copyright certain parts of Java, an "open-source," or publicly available, software language.
Earlier in the case, estimates of potential damages against Google ran as high as US$6.1 billion.
But Google successfully narrowed Oracle's patent claims, so that the bulk of Google's damages exposure now derives mostly on copyright claims.
Oracle is seeking roughly US$1 billion in copyright damages.
The seven woman, five man jury will begin hearing evidence on Oracle's patents after rendering the copyright verdict. A third phase to decide damages would come after the patent testimony.
The case in U.S. District Court, Northern District of California, is Oracle America, Inc v. Google Inc, 10-3561.
(Reporting By Malathi Nayak; Editing by Gerald E. McCormick, Bernard Orr)