But the death toll may be even higher as a fatal bomb blast on Wednesday night has now been linked to the attack.
Police say one person was killed and at least seven were injured in the explosion, which destroyed one house and damaged all the adjacent ones.
The house was in a residential area in Alcanor, about 120 miles south of Barcelona. Officials say the explosion was caused by butane gas, of which around 20 bottles were found in the wreckage — far more gas than what a normal house could use.
Circumstances around this explosion have not yet been confirmed, but experts are currently speculating based on the amount of gas that this was part of a larger bomb attack plan, and that it may have gone wrong.