A homicide investigation is underway after a Harlingen teen was shot and killed in Cameron County, the sheriff's office announced Tuesday. 

Authorities say shortly before 2 a.m., two male subjects drove up to a Harlingen police officer seeking help for their friend who was in the back seat and had been shot, according to a news release from the Cameron County Sheriff's Office. 

The subject was identified as 18-year-old Jaime Medina of Harlingen. Medina received medical aid on site, and later died at a hospital. 

Authorities say the shooting took place west of Farm-to-Market Road 800 on westbound Expressway 83 in Harlingen.

The Cameron County Sheriff's Office said Wednesday that all findings obtained by investigators have been handed over to Harlingen police.