A series of suspicious fires have broken out along Interstate 580 in the past few days, with another blaze dubbed the "Grant Fire" igniting early Saturday morning.

California Highway Patrol confirmed that multiple grass fires were deliberately set on the right shoulder across an eight-mile stretch of I-580 near the Altamont Pass in eastern Alameda County, starting around 6:15 a.m. Saturday, according to KRON4.

Firefighting crew are actively working to contain the Grant Fire, which started as a 25-acre fire along the freeway near Grant Line Road, between the I-580 and 205 split near Tracy, according to Cal Fire. The fire grew to approximately 75 acres and was 85% contained around 11 a.m., according to Cal Fire’s most recent update.

Expect traffic delays, as well, because the number four lane for I-580 nearby is closed at this time.

Authorities are reportedly investigating it as possible arson incident. Witnesses described a person of interest wearing a blue shirt and black pants, seen near one of the fires on the Portola Avenue under-crossing, driving a newer-model white truck, as KRON reported.

Another fire late Friday night also added to the challenges, according to KPIX. That fire, called the Flynn fire, sparked along Interstate 580 near Flynn Road, reaching a sprawling 41 acres before being fully contained by the Alameda County Fire Department around midnight.

Authorities are urging anyone with relevant information about the fires or the individual linked to the white truck to contact the California Highway Patrol at 707-641-8300.

Feature image of the Grant Fire via CHP Dublin.