A man who witnessed a fatal deputy-involved shooting in Vista Wednesday said the suspect had been laying on the ground and was unarmed at the time.

"They shoot him right there. 'Boom, boom, boom,'" the witness said. He did not want to be identified by name.

Around 10:30 a.m., deputies chased a man, identified as Jonathon Coronel, 24, with a warrant for a probation violation into the witness' yard on North Melrose Drive near Knoll Road.

According to the San Diego County Sheriff's Department (SDSO), Coronel was a 24-year-old documented gang member.

The witness said he had been working in the patio area at the time. Coronel tried to hide near the children's pool and asked him to keep quiet.

“I looked at my wife and my two daughters. I was, 'No. I can't put my daughters in danger,'" he told NBC 7.

The witness said he told Coronel to give up and not resist authorities.

"I was worried for my daughter[s], for my family," he said.

SDSO said there was a confrontation between the pursuing deputy and the suspect before the deputy fired several times, killing the suspect.

According to the witness, the suspect was unarmed and lying on his stomach.

"I have the suspect down on the ground already and they shot at him. So that was wrong," the witness said.

He added it was an incident he won't soon forget.

"Emotional. Big time, I mean," he said.

An SDSO statement did not indicate if the suspect was armed at the time of the shooting. SDSO officials said Coronel was shot multiple times.

"There was a confrontation between the deputy and the suspect, which resulted in the deputy firing his weapon multiple times, striking the suspect," the statement reads.

The incident is under investigation by the SDSO homicide unit.