A mistrial was declared after a jury deadlocked Tuesday in the case of a Border Patrol agent accused of gunning down an illegal immigrant without provocation.

Jurors couldn't reach a verdict against U.S Border Patrol Agent Nicholas Corbett on three possible charges: second-degree murder, manslaughter or negligent homicide. His first trial in March also ended with the jury deadlocked.

The shooting in January 2007 caused an international uproar, with Mexican President Felipe Calderon condemning it and calling for a complete investigation.

Francisco Javier Dominguez Rivera, 22, of Puebla, Mexico, was crossing the southern Arizona desert with two of his brothers and one's girlfriend when Corbett drove up in his Border Patrol truck and started to arrest them.

Dominguez's companions all testified he was going to his knees to surrender when Corbett shot Dominguez without provocation. The defense said the agent shot in self-defense after Dominguez tried to smash his head with a rock.

The defense also claimed the three companions were pressured by Mexican government officials eager to see the U.S. agent prosecuted.

The case involved state criminal charges filed by the Cochise County Attorney, but it was tried in U.S. District Court in Tucson because Corbett is a federal agent.

Special prosecutor Grant Woods said the county attorney's office showed courage in bringing the case.

"In our state of Arizona, we stood up for the basic human rights of the victim and his family here and the justice system performed as well as it could," Woods said.

Defense attorney Sean Chapman says he's disappointed the jury didn't acquit.

"It's our understanding in the jury note that was sent out it was actually 11 to 1 in favor of acquittal in this case, with one holdout," Chapman said.

Woods said he's not sure whether Corbett will be retried.