A jury decided on Tuesday that a man accused of murdering a Sikh gas station owner in retaliation for the terror attacks of September 11, 2001 is guilty.

Jurors in Mesa, Arizona, found Frank Roque (44) guilty on six counts of first-degree murder, attempted murder, drive-by shooting and endangerment.

Defense attorneys argued that Roque was mentally ill when he gunned down Balbir Singh Sodhi (49) four days after September 11, 2001.

Prosecutors, however, said Roque was a racist and knew what he was doing when he killed Sodhi, whose turban and beard marked him as a foreigner.

For four weeks, the jury heard testimony from expert witnesses called by both sides to attest to Roque's sanity or lack thereof.

In closing arguments on Monday, defense lawyer Dan Patterson portrayed Roque as a fragile man tipped over the edge by the horrific events of September 11. "There was lunacy at work on a grand scale on September 11. There was also lunacy at work on a smaller scale in Mesa."

Prosecutor Vince Imbordino said Roque was driven by hatred, not the voice of God telling him to "kill the devil."

"You don't wake up on September 11 and become a racist, you've been one a long time," he told the court. "It's not mental illness – it's anger, revenge, hatred."

Roque could face the death penalty, which is the outcome prosecutors are seeking. Or, he could be sent to prison for life.

Analysts say the defense strategy was aimed at saving Roque from execution. They say defense witnesses have created enough doubts about Roque's sanity for jurors to forego the death penalty.

The court will convene on Thursday to discuss mitigation, according to Arizona law. A court spokeswoman said there could be a decision early next week whether Roque lives or dies.