(Reuters) - The Supreme Court handed a victory to gun control advocates on Monday by upholding the conviction of a former police officer from Virginia who lied when he stated he was buying a handgun for himself when it actually was for a relative.

In a 5-4 ruling focused on the role of what is known as a "straw buyer" for a gun, the court upheld Bruce Abramski's conviction for making a false statement when he bought the gun. He had filled out a form, required under federal law, saying he was the prospective owner, when the gun was intended for his uncle.

The court was split along ideological lines, with the liberal wing in the majority with swing vote Justice Anthony Kennedy. The dissenting justices, from the conservative bloc of the court, said the federal law in question makes no distinction between people who purchased guns for themselves and buyers who intend to pass the gun on to others.

Abramski, a former police officer, said he purchased the gun for Angel Alvarez from a gun store in Collinsville, Virginia, in 2009 because he thought he would be able to get a discount. Abramski appealed his conviction in part because Alvarez, who lives in Pennsylvania, was not legally barred from owning a handgun.

Writing for the majority, Justice Elena Kagan rejected Abramski's arguments.

"No piece of information is more important under federal firearms law than the identity of a gun’s purchaser - the person who acquires a gun as a result of a transaction with a licensed dealer," Kagan wrote.

"Had Abramski admitted that he was not that purchaser, but merely a straw - that he was asking the dealer to verify the identity of, and run a background check on, the wrong individual - the sale here could not have gone forward," Kagan added.

Under federal law, firearm buyers undergo background checks with the intent of keeping guns from people who may be prohibited from owning them, like convicted felons.

"Putting true numbskulls to one side, anyone purchasing a gun for criminal purposes would avoid leaving a paper trail by the simple expedient of hiring a straw," Kagan added.

Abramski pleaded guilty in 2011 and was sentenced to five years of probation. The Richmond, Virginia-based 4th U.S. Circuit Court of Appeals upheld his conviction in a January 2013 ruling.

Justice Antonin Scalia wrote a dissenting opinion saying that the majority "makes it a federal crime for one lawful gun owner to buy a gun for another lawful gun owner."

Gun control advocates hailed the ruling. "This is a very big and very positive decision that will save lives by keeping guns out of the hands of dangerous people," Dan Gross, president of the Brady Center to Prevent Gun Violence, said in a statement.

Gross said the justices "rejected efforts by the corporate gun lobby to undermine federal gun laws" in favor of "sensible" gun laws.

The case is Abramski v. United States, U.S. Supreme Court, No. 12-1493.

Pennsylvania