SAN DIEGO - All lanes of the westbound Interstate 8 in the Mission Valley area have been reopened following the discovery of a body along the freeway Friday morning.

The California Highway Patrol began receiving calls around 6:20 a.m. reporting that a man carrying a bag was walking along the westbound lanes near the Interstate 805 interchange, CHP Officer Robert Catano said. About 10 minutes later, the pedestrian was seen lying on the roadside.

Police say the victim was a white male in his mid-30s, who appears to have been a transient. Investigators say the man had trauma to his upper body, but that it did not appear that he had been hit by a vehicle. His identity is not yet known.

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The emergency response prompted the CHP to shut down multiple westbound I-8 lanes and issue a Sig Alert.

Three lanes of I8 West still closed near 805. If this lasts much longer, it may impact #traffic for tonight's @Chargers game. @nfl @10news — Jared Aarons (@10NewsAarons) August 19, 2016

Two lanes were reopened just before 7 a.m., but the No. 4, 5 and 6 lanes were shut down due to the investigation for an extended period. Drivers heading west were urged to avoid the area and find alternate routes.

Drivers coming from the East County were advised to use state Route 52 or state Route 94.

A stretch of Camino Del Rio North, which runs parallel with westbound I-8, was shut down from Mission City Parkway to Ward Road as part of the investigation. The closure was expected to last for an undetermined amount of time.

By 1 p.m., all lanes on the westbound Interstate 8 had been reopened.

Investigators told 10News they are looking for a white BMW sedan -- driven by a man believed to be African-American -- that may have been involved in the incident. The incident is not being classified as a hit-and-run at this point, officials noted.

San Diego Police Department homicide detectives have taken over the investigation. They want to talk to anyone who may have seen the victim prior to or after the body was discovered.