California authorities are asking the public to help find the man who shot and killed an officer during a traffic stop, and claim the suspect is an undocumented immigrant.

Cpl. Ronil Singh, 33, was shot and killed early Wednesday morning, shortly after he radioed in that he was pulling over a gray pickup truck with no license plates in the small town of Newman, Calif., according to the Associated Press. Newman is located about 100 miles southeast of San Francisco.

Although Stanislaus County Sheriff Adam Christianson did not identify the suspect by name during a news conference on Thursday, he did say the man was in the country illegally. “He doesn’t belong here, he is a criminal. We will arrest him and we will bring him to justice.” Christianson said.

According to the Modesto Bee, Christianson met with President Trump in May at the White House to discuss immigration and sanctuary laws. Also in attendance were then-ICE Director Thomas Homan, then-House Majority Leader Kevin McCarthy, and then-Attorney General Jeff Sessions. During the meeting, Christianson thanked Trump for “being a defender of the rule of law, and for your overwhelming support of public safety, and for standing with the men and women who put their lives on the line every day.”

After Thursday’s press conference, President Trump weighed in on the manhunt on Twitter, using it to back his argument for the border wall, which many experts agree is not an effective deterrent for migrants looking to enter the U.S. According to multiple studies, undocumented immigrants do not statistically commit crimes at higher rates than Americans citizens or those who enter the country legally.

California authorities said Thursday they believe the suspect is still in Stanislaus County. “We will find him, we will arrest him and we will bring him to justice,” Christianson said.

On Wednesday, the sheriff’s office released surveillance footage of the alleged suspect purchasing a 12-pack of beer at at a convenience store.

Officers also said that following a tip, they found the alleged suspect’s grey Dodge Ram truck on an abandoned road in Newman on Wednesday afternoon, and said that a state-wide man hunt is on.

Newman Police Chief Randy Richardson fought back tears on Thursday as he remembered Singh, a Fiji native who Richardson said came to the United States for the sole purpose of becoming a police officer. Singh joined the force in 2011 and was one of just 12 members of the Newman Police Department. He is survived by his wife and 5-month-old son.

“This was not supposed to happen here,” Richardson told reporters on Thursday.

“Please remember the man,” Richardson also said. “Please remember the husband. Remember what he was, what he came to this country to do. Yes, he was a police officer, but most importantly he was a human being.”