An investigation is underway after an early morning fire on Friday damaged multiple trucks at the Phoenix headquarters of electric truck manufacturer Nikola Corp. 

The incident, which was first reported just before 5 a.m. MT, caused damage to five electric trucks, according to a CNN report. In a tweet, the electric truck startup called the fire suspicious.

“Foul play is suspected as a vehicle was seen in the area of the affected trucks just prior to the incident and an investigation is underway,” the tweet reads.

Early this morning behind our Phoenix headquarters, a fire occurred which affected multiple battery electric trucks. No one has been injured. Foul play is suspected as a vehicle was seen in the area of the affected trucks just prior to the incident and an investigation is…

— Nikola Motor Company (@nikolamotor) June 23, 2023

Hazardous materials crews from the Phoenix Fire Department and the Tempe Fire Medical Rescue Department responded to the scene

Hazardous Materials crews from @PHXFire & @TempeFire are on the scene of multiple electric semi trucks on fire near 40th St and Broadway Rd, please avoid the area. pic.twitter.com/RGivsaJAMT

— Phoenix Fire Dept. (@PHXFire) June 23, 2023

No injuries were reported. 

The news comes one week after the company announced it slashed nearly 300 jobs as its cash to run the business shrinks and amid ongoing turmoil with the company’s founder, Trevor Milton, who was convicted of defrauding investors in October. 

Read more about Nikola here.