The man who was shot and killed by sheriff's detectives Thursday after investigators say he tried to run over one of their own, was part of a larger on-going investigation, the Salt Lake County Sheriff's Office said Friday.

The sheriff's narcotics unit was keeping surveillance on 49-year-old Jose Enrique Gelpi Friday. Investigators attempted to pull over Gelpi in his vehicle near 600 East and 600 South but he fled instead, said Lt. Paul Jaroscak.

Gelpi jumped the median along 600 East, plowed over a small tree, then hit a parked car on the opposite side of the road before plowing through a wood fence and ending up in the front yard of the house on the corner. During the incident, Gelpi also hit the narcotics sergeant with his vehicle. The sergeant suffered a minor leg injury and was treated at the scene.

After the sergeant was hit, a 30-year-old deputy who has been with the sheriff's office for 5 years, shot Gelpi. The sheriff's office is withholding the name of the deputy because he was working undercover. The office also declined Friday to go into detail about what kind of investigation the narcotics unit was conducting.

"It was part of a larger investigation we hope to wrap up and talk about in the near future," Jaroscak said.

Court records show Gelpi is being prosecuted for a felony drug possession charge in another incident and had appeared in court Wednesday in another case for misdemeanor assault. The charge was dismissed without prejudice. Gelpi pled guilty to a possession of drug paraphernalia charge in 2007.