EL MONTE, Calif. (KABC) -- A woman was found dead inside a vehicle on the side of the eastbound I-10 freeway in El Monte, causing an hours-long closure during the investigation Tuesday morning.Around 4 a.m., a call regarding a disabled car came in. A woman in her mid-30s was found on the side of I-10 before daybreak near the Peck Road exit, according to the CHP.The Latina woman was found inside the vehicle with a gunshot wound to the head, authorities said. She was found by a passing tow truck driver. No other cars were involved, according to the CHP.Before dawn, Officers appeared to be searching the roadway with flashlights. A white car with a yellow covering over the driver's side window could be seen by the side of the highway.Authorities said the incident could have happened in a different location. The car had hit the guardrail along the side of the road and continued for a little before coming to a stop.The freeway was shut down for hours and reopened shortly before 2 p.m.Anyone who has seen or heard anything related to the case is urged to call the police.