(CNN) -- Investigators were searching for suspects Wednesday after a shooting that killed one Border Patrol agent and wounded another near the U.S.-Mexican border in Arizona.
The agents came under fire near Naco, Arizona, Tuesday after responding to a sensor that had gone off near the border, the U.S. Customs and Border Protection agency said.
Authorities identified the agent killed as 30-year-old Nicholas Ivie. A native of Provo, Utah, he joined the Border Patrol in January 2008. Ivie is survived by his wife and two young children.
"I'm just in shock right now and sad," sister-in-law Michelle Ivie told CNN affiliate KUTV. "Nick was the most tenderhearted, kind, gentle, loving person you could ever meet."
He was the youngest of five children, KUTV reported.
In a statement, his parents and brothers said: "We are extremely proud of Nick and for his service both in his community and our country. He loved what he did and he gave it his all, including his life. Our thoughts and prayers are with his wonderful wife and his two beautiful girls."
President Barack Obama called Ivie's family to offer his condolences and thank the family for Ivie's service, the White House said.
"The president told the family they are in his thoughts and prayers and made clear that his administration was doing everything it could to locate those responsible for this tragic event," a White House statement said.
The agent who was wounded was not identified. After the shooting, he was airlifted to an area hospital and with non-life-threatening injuries.
He was released from the hospital Wednesday, said Jeremy Copeland, an agent with the Tucson Sector of U.S. Border Patrol.
Customs and Border Protection "appreciates the support it has received from its law enforcement partners and community members from around the nation," Copeland added.
Tuesday, Customs and Border Protection Deputy Commissioner David Aguilar noted that Ivie "died in the line of duty, protecting our nation against those who threaten our way of life.
"His death only strengthens our resolve to enforce the rule of law and bring those responsible to justice," Aguilar said in a statement.
The FBI is conducting a joint investigation with the Cochise County Sheriff's Office. Investigators have not yet found the weapon used in the shooting, a law enforcement official said.
James Turgal, special agent in charge of the FBI for the Phoenix division, declined to say whether the agents involved in the incident returned fire. He also declined to comment on whether any weapons had been found.
Lanny Breuer, assistant attorney general for the Criminal Division of the Justice Department, said investigators are at the scene.
"Every time that a law enforcement person is either killed or shot or injured in the line of duty, we have to take a moment and think of our families and think of the heroes involved," Breuer said.
Ivie is the 14th agent killed in the line of duty since 2008, including three this year.
He was killed near a border station recently named for Brian Terry, whose 2010 death led to the public disclosure of the botched Fast and Furious gun-smuggling sting, according to Sen. Chuck Grassley of Iowa.
"There's no way to know at this point how the agent was killed, but because of Operation Fast and Furious, we'll wonder for years if the guns used in any killing along the border were part of an ill-advised gunwalking strategy sanctioned by the federal government. It's a sad commentary," the Republican senator said.
Turgal declined to comment on whether there could be a possible Fast and Furious connection to Tuesday's killing.
CNN's Leslie Tripp, Ed Payne, Deanna Proeller and Carol Cratty contributed to this report.